🐛 Fix CD-ROM backing ISO library item size check

[dilyar85]

What does this PR do, and why is it needed?

This PR uses apimachinery.resource.Quantity's IsZero() function to correctly check if the CD-ROM's backing ISO library library item is empty. The originally used Size () function returns the number of bytes required to marshal the value to protobuf (i.e. the statement would always be false as that function returns 3 for zero-size quantity).

Which issue(s) is/are addressed by this PR?

Fixes N/A.

Are there any special notes for your reviewer:

Opened a PR to k/k to add godoc for this function: kubernetes/kubernetes#129256

Please add a release note if necessary:

Fix CD-ROM backing ISO library item size check to use resource.IsZero() function.

[akutz]

Thanks @dilyar85 !

[github-actions]

Package	Line Rate	Health
github.com/vmware-tanzu/vm-operator/controllers/contentlibrary/clustercontentlibraryitem	82%	➖
github.com/vmware-tanzu/vm-operator/controllers/contentlibrary/contentlibraryitem	86%	➖
github.com/vmware-tanzu/vm-operator/controllers/contentlibrary/utils	97%	✔
github.com/vmware-tanzu/vm-operator/controllers/infra/capability/configmap	86%	➖
github.com/vmware-tanzu/vm-operator/controllers/infra/capability/crd	93%	✔
github.com/vmware-tanzu/vm-operator/controllers/infra/configmap	71%	❌
github.com/vmware-tanzu/vm-operator/controllers/infra/node	77%	❌
github.com/vmware-tanzu/vm-operator/controllers/infra/secret	77%	❌
github.com/vmware-tanzu/vm-operator/controllers/infra/validatingwebhookconfiguration	85%	➖
github.com/vmware-tanzu/vm-operator/controllers/infra/zone	76%	❌
github.com/vmware-tanzu/vm-operator/controllers/storageclass	95%	✔
github.com/vmware-tanzu/vm-operator/controllers/storagepolicyquota	97%	✔
github.com/vmware-tanzu/vm-operator/controllers/util/encoding	73%	❌
github.com/vmware-tanzu/vm-operator/controllers/virtualmachine/storagepolicyusage	99%	✔
github.com/vmware-tanzu/vm-operator/controllers/virtualmachine/virtualmachine	87%	➖
github.com/vmware-tanzu/vm-operator/controllers/virtualmachine/volume	87%	➖
github.com/vmware-tanzu/vm-operator/controllers/virtualmachineclass	75%	❌
github.com/vmware-tanzu/vm-operator/controllers/virtualmachinepublishrequest	81%	➖
github.com/vmware-tanzu/vm-operator/controllers/virtualmachinereplicaset	68%	❌
github.com/vmware-tanzu/vm-operator/controllers/virtualmachineservice	83%	➖
github.com/vmware-tanzu/vm-operator/controllers/virtualmachineservice/providers	92%	✔
github.com/vmware-tanzu/vm-operator/controllers/virtualmachinesetresourcepolicy	80%	➖
github.com/vmware-tanzu/vm-operator/controllers/virtualmachinewebconsolerequest	72%	❌
github.com/vmware-tanzu/vm-operator/controllers/virtualmachinewebconsolerequest/v1alpha1	72%	❌
github.com/vmware-tanzu/vm-operator/controllers/virtualmachinewebconsolerequest/v1alpha1/conditions	88%	➖
github.com/vmware-tanzu/vm-operator/controllers/virtualmachinewebconsolerequest/v1alpha1/patch	78%	❌
github.com/vmware-tanzu/vm-operator/pkg/bitmask	100%	✔
github.com/vmware-tanzu/vm-operator/pkg/builder	95%	✔
github.com/vmware-tanzu/vm-operator/pkg/conditions	88%	➖
github.com/vmware-tanzu/vm-operator/pkg/config	100%	✔
github.com/vmware-tanzu/vm-operator/pkg/config/capabilities	100%	✔
github.com/vmware-tanzu/vm-operator/pkg/config/env	100%	✔
github.com/vmware-tanzu/vm-operator/pkg/context/generic	100%	✔
github.com/vmware-tanzu/vm-operator/pkg/context/operation	100%	✔
github.com/vmware-tanzu/vm-operator/pkg/patch	78%	❌
github.com/vmware-tanzu/vm-operator/pkg/prober	91%	✔
github.com/vmware-tanzu/vm-operator/pkg/prober/probe	90%	✔
github.com/vmware-tanzu/vm-operator/pkg/prober/worker	77%	❌
github.com/vmware-tanzu/vm-operator/pkg/providers/vsphere	75%	❌
github.com/vmware-tanzu/vm-operator/pkg/providers/vsphere/client	80%	➖
github.com/vmware-tanzu/vm-operator/pkg/providers/vsphere/clustermodules	71%	❌
github.com/vmware-tanzu/vm-operator/pkg/providers/vsphere/config	89%	✔
github.com/vmware-tanzu/vm-operator/pkg/providers/vsphere/contentlibrary	74%	❌
github.com/vmware-tanzu/vm-operator/pkg/providers/vsphere/credentials	100%	✔
github.com/vmware-tanzu/vm-operator/pkg/providers/vsphere/network	80%	➖
github.com/vmware-tanzu/vm-operator/pkg/providers/vsphere/placement	79%	❌
github.com/vmware-tanzu/vm-operator/pkg/providers/vsphere/session	71%	❌
github.com/vmware-tanzu/vm-operator/pkg/providers/vsphere/storage	44%	❌
github.com/vmware-tanzu/vm-operator/pkg/providers/vsphere/sysprep	100%	✔
github.com/vmware-tanzu/vm-operator/pkg/providers/vsphere/vcenter	81%	➖
github.com/vmware-tanzu/vm-operator/pkg/providers/vsphere/virtualmachine	84%	➖
github.com/vmware-tanzu/vm-operator/pkg/providers/vsphere/vmlifecycle	69%	❌
github.com/vmware-tanzu/vm-operator/pkg/record	87%	➖
github.com/vmware-tanzu/vm-operator/pkg/topology	91%	✔
github.com/vmware-tanzu/vm-operator/pkg/util	87%	➖
github.com/vmware-tanzu/vm-operator/pkg/util/annotations	100%	✔
github.com/vmware-tanzu/vm-operator/pkg/util/cloudinit	89%	✔
github.com/vmware-tanzu/vm-operator/pkg/util/cloudinit/validate	91%	✔
github.com/vmware-tanzu/vm-operator/pkg/util/image	100%	✔
github.com/vmware-tanzu/vm-operator/pkg/util/kube	89%	➖
github.com/vmware-tanzu/vm-operator/pkg/util/kube/cource	100%	✔
github.com/vmware-tanzu/vm-operator/pkg/util/kube/internal	100%	✔
github.com/vmware-tanzu/vm-operator/pkg/util/kube/proxyaddr	73%	❌
github.com/vmware-tanzu/vm-operator/pkg/util/kube/spq	100%	✔
github.com/vmware-tanzu/vm-operator/pkg/util/netplan	100%	✔
github.com/vmware-tanzu/vm-operator/pkg/util/ovfcache	75%	❌
github.com/vmware-tanzu/vm-operator/pkg/util/ovfcache/internal	100%	✔
github.com/vmware-tanzu/vm-operator/pkg/util/paused	100%	✔
github.com/vmware-tanzu/vm-operator/pkg/util/ptr	100%	✔
github.com/vmware-tanzu/vm-operator/pkg/util/resize	97%	✔
github.com/vmware-tanzu/vm-operator/pkg/util/vmopv1	93%	✔
github.com/vmware-tanzu/vm-operator/pkg/util/vsphere/client	64%	❌
github.com/vmware-tanzu/vm-operator/pkg/util/vsphere/vm	79%	❌
github.com/vmware-tanzu/vm-operator/pkg/util/vsphere/watcher	87%	➖
github.com/vmware-tanzu/vm-operator/pkg/vmconfig	95%	✔
github.com/vmware-tanzu/vm-operator/pkg/vmconfig/crypto	98%	✔
github.com/vmware-tanzu/vm-operator/pkg/webconsolevalidation	100%	✔
github.com/vmware-tanzu/vm-operator/services/vm-watcher	92%	✔
github.com/vmware-tanzu/vm-operator/webhooks/common	100%	✔
github.com/vmware-tanzu/vm-operator/webhooks/persistentvolumeclaim/validation	95%	✔
github.com/vmware-tanzu/vm-operator/webhooks/unifiedstoragequota/validation	89%	✔
github.com/vmware-tanzu/vm-operator/webhooks/virtualmachine/mutation	87%	➖
github.com/vmware-tanzu/vm-operator/webhooks/virtualmachine/validation	95%	✔
github.com/vmware-tanzu/vm-operator/webhooks/virtualmachineclass/mutation	62%	❌
github.com/vmware-tanzu/vm-operator/webhooks/virtualmachineclass/validation	89%	➖
github.com/vmware-tanzu/vm-operator/webhooks/virtualmachinepublishrequest/validation	92%	✔
github.com/vmware-tanzu/vm-operator/webhooks/virtualmachinereplicaset/validation	90%	✔
github.com/vmware-tanzu/vm-operator/webhooks/virtualmachineservice/mutation	67%	❌
github.com/vmware-tanzu/vm-operator/webhooks/virtualmachineservice/validation	92%	✔
github.com/vmware-tanzu/vm-operator/webhooks/virtualmachinesetresourcepolicy/validation	89%	✔
github.com/vmware-tanzu/vm-operator/webhooks/virtualmachinewebconsolerequest/v1alpha1/validation	92%	✔
github.com/vmware-tanzu/vm-operator/webhooks/virtualmachinewebconsolerequest/validation	92%	✔
Summary	83% (10674 / 12807)	➖

Minimum allowed line rate is 79%