fix: apply authorization policy in user namespace to allow istio traffic

[NohaIhab]

closes canonical/notebook-operators#311 and #355

Testing

1. deploy charmed kubeflow latest/edge
2. refresh the kfp-profile-controller charm to the one from this PR

juju refresh kfp-profile-controller --channel=latest/edge/pr-356 

3. log in to the dashboard and create a namespace
4. check AuthorizationPolicy objects in the user's namespace, expect 2 objects:

kubectl get authorizationpolicies.security.istio.io -n admin
NAME                            AGE
ns-owner-access-istio-charmed   15s
ns-owner-access-istio           12s

5. create a notebook and verify there are no 403 logs from the jupyter-controller container
6. create a data passing pipeline and verify that you can download artifacts from pipeline steps

[NohaIhab]

closing in favour of #360 to point to branch 1.8-updates-dev-branch