feat: add support for identity service server and updating identity service

[afarbos]

What type of PR is this?

/kind feature

What this PR does / why we need it:

Following #1366, the goal of this PR is to expose the server used by identity enabling easier authentication without prior cluster access or secret manipulation and update of the identity service config.

Doc: https://cloud.google.com/kubernetes-engine/docs/how-to/oidc

example:

apiVersion: infrastructure.cluster.x-k8s.io/v1beta1
kind: GCPManagedControlPlane
metadata:
  creationTimestamp: "2024-12-17T21:31:23Z"
  finalizers:
  - gcpmanagedcontrolplane.infrastructure.cluster.x-k8s.io
  generation: 2
  labels:
    cluster.x-k8s.io/cluster-name: foo
  name: foo
  namespace: bar
  ownerReferences:
  - apiVersion: cluster.x-k8s.io/v1beta1
    blockOwnerDeletion: true
    controller: true
    kind: Cluster
    name: foo
    uid: ce97e489-f1e6-4fbb-bcb9-a34f98d1eab7
  resourceVersion: "16165"
  uid: 7ceb8c04-ab91-4b3c-967a-adf3c9e9be30
spec:
  clusterName: foo
  controlPlaneVersion: 1.30.5
  enableIdentityService: true
  endpoint:
    host: 108.59.84.44
    port: 443
  location: us-central1
  project: "123456"
status:
  conditions:
  - lastTransitionTime: "2024-12-17T22:08:04Z"
    status: "True"
    type: Ready
  - lastTransitionTime: "2024-12-17T22:08:04Z"
    reason: GKEControlPlaneCreated
    severity: Info
    status: "False"
    type: GKEControlPlaneCreating
  - lastTransitionTime: "2024-12-17T22:08:04Z"
    status: "True"
    type: GKEControlPlaneReady
  - lastTransitionTime: "2024-12-17T22:27:36Z"
    reason: GKEControlPlaneUpdated
    severity: Info
    status: "False"
    type: GKEControlPlaneUpdating
  currentVersion: 1.30.5
  identityServiceServer: https://34.134.50.254:443 # <- NEW FIELD HERE
  initialized: true
  ready: true

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 #

Special notes for your reviewer:

Please confirm that if this PR changes any image versions, then that's the sole change this PR makes.

TODOs:

• squashed commits
• includes documentation
• adds unit tests

Release note:

GKEManagedControlPlane: Add support for identity service server in status and updating identity service 

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: afarbos
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[k8s-ci-robot]

Hi @afarbos. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[afarbos]

I ran locally: make generate, make verify and make test all pass.
I also verified everything works using tilt.

[salasberryfin]

/ok-to-test

[salasberryfin]

Thanks @afarbos. Could you please rebase your commits to squash them into logical changes? This helps maintain a clean history and simplifies reverts, if needed.

[afarbos]

Thanks @afarbos. Could you please rebase your commits to squash them into logical changes? This helps maintain a clean history and simplifies reverts, if needed.

sounds good, done!

3 commits:

• fix local dev
• fix add update logic for identity server
• feat expose identity service server

[afarbos]

note: this also fix the error it should have been updateErr, now everything is err