Changing admission controller settings

[hyperbolic2346]

What this PR does / why we need it:
By default, the admission controller settings in a CDK cluster didn't match the set recommended here:
https://kubernetes.io/docs/admin/admission-controllers/#is-there-a-recommended-set-of-admission-controllers-to-use

Now they do.
Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #
https://github.com/juju-solutions/bundle-canonical-kubernetes/issues/517
Special notes for your reviewer:

Release note:

Updated admission controller settings for Juju deployed Kubernetes clusters

[dims]

/ok-to-test

[Cynerva]

/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Cynerva, hyperbolic2346

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Automatic merge from submit-queue (batch tested with PRs 61402, 61143, 61427, 60592). If you want to cherry-pick this change to another branch, please follow the instructions here.