🐛 Stop writing zero values for spec.controlPlaneEndpoint to ControlPlane objects

[faiq]

What this PR does / why we need it:

If spec.ControlPlaneEndpoint is set on the control plane object we should ignore that when merging the objects together. We follow a similar pattern for infrastructureCluster objects.

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 #

/area clusterclass

[faiq]

/assign @sbueringer

[sbueringer]

Thank you!

/test pull-cluster-api-e2e-main-gke
/lgtm
/approve

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 51a8271791bf96cac0b626cacc62fdb741349859

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: sbueringer

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [sbueringer]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[faiq]

/cherrypick release-1.10 release-1.11

[k8s-infra-cherrypick-robot]

@faiq: new pull request created: #12981

In response to this:

/cherrypick release-1.10 release-1.11

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[sbueringer]

/cherry-pick release-1.11

[sbueringer]

You'll have to open a manual cherry-pick PR for release-1.10

[k8s-infra-cherrypick-robot]

@sbueringer: new pull request created: #12982

In response to this:

/cherry-pick release-1.11

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.