⚠️ remove ClusterConfiguration.UseHyperKubeImage from v1alpha4

[ludusrusso]

What this PR does / why we need it:

This PR removes ClusterConfiguration.UseHyperKubeImage from v1alpha4 as discussed in #4542

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 #4542

/cc @fabriziopandini
/cc @vincepri

[k8s-ci-robot]

Hi @ludusrusso. 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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[fabriziopandini]

/ok-to-test

[fabriziopandini]

Thanks @ludusrusso !
Only a couple of nits from my side

[k8s-ci-robot]

@ludusrusso: The following test failed, say /retest to rerun all failed tests:

Test name	Commit	Details	Rerun command
pull-cluster-api-apidiff-main	db47368	link	/test pull-cluster-api-apidiff-main

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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[vincepri]

/lgtm

[fabriziopandini]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: fabriziopandini

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