Fix all kubenetes mixins according to pint

[QuentinBisson]

Before adding a new alerting rule into this repository you should consider creating an SLO rules instead.
SLO helps you both increase the quality of your monitoring and reduce the alert noise.

• How to create a SLO rule: https://github.com/giantswarm/sloth-rules#how-to-create-a-slo
• Documentation: https://intranet.giantswarm.io/docs/monitoring/slo-alerting/

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Towards: https://github.com/giantswarm/...

This PR fixes mixins according to basic pint recommendations

Checklist

• Update CHANGELOG.md
• Add Unit tests
• Follow Alert structure
• Consider creating a dashboard (guidelines) (if it does not exist already) to help oncallers monitor the status of the issue.
• Request review from oncall area, as well as team (e.g: oncall-kaas-cloud GitHub group).

[hervenicol]

Have upstream mixins been updated accordingly? So next time we upgrade we don't have to re-apply all these changes?

[QuentinBisson]

Which ones ? The Kubernetes ones most likely not. Thé Loki and Mimir ones nope but that's s in other PRs and it's sadly not ready yet anyway

[QuentinBisson]

The kubernetes mixin script was updated but for loki and mimir it's currently not merged

[QuentinBisson]

@hervenicol I added the upgrade scripts to add the labels using sed in #1131 for both loki and mimir and for the kubernetes mixins in this PR.

The loki and mimir scripts added in #1131 will eventually be moved to the mimir and loki app (end goal of https://github.com/giantswarm/giantswarm/issues/30309 and https://github.com/giantswarm/giantswarm/issues/30310 once we upgraded to loki 3 and ongoing issues are fixed)

It also needs giantswarm/dashboards#538 to be merged which renames all cluster occurences to cluster_id as recording rules are generated like that

[QuantumEnigmaa]

LGTM

[marieroque]

LGTM