Do not use version when indexing Used resources in Usage Handler

[turkenh]

Description of your changes

This PR fixes a bug in the Usage handler with multi versioned CRDs by dropping the usage of the version from the index string used by the handler.

Example Scenario:

We define the following Usage resource:

apiVersion: apiextensions.crossplane.io/v1alpha1
kind: Usage
metadata:
  name: do-not-delete-namespace
spec:
  of:
    apiVersion: kubernetes.crossplane.io/v1alpha1
    kind: Object
    resourceRef:
      name: ns-test-namespace
  reason: Namespace should not be deleted

For the following Object:

apiVersion: kubernetes.crossplane.io/v1alpha1
kind: Object
metadata:
  name: ns-test-namespace
spec:
  forProvider:
    manifest:
      apiVersion: v1
      kind: Namespace
      metadata:
        name: test-namespace
  readiness:
    policy: SuccessfulCreate

And we're running the latest provider kubernetes which has a v1alpha2 as the storage version for Object. So, when we get the Object back after creation, we already see the version as v1alpha2.

Prior to this PR, deletion of the ns-test-namespace Object is not blocked by the Usage since we were using the version in the indexer, so v1alpha1 Objects blocked but not v1alpha2s. With this PR, we will drop the version from the index, hence it will block Objects independent of versions.

Related previous discussion: #4215 (comment)

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[phisco]

Thanks @turkenh!

[github-actions]

Backport failed for release-1.14, because it was unable to cherry-pick the commit(s).

Please cherry-pick the changes locally and resolve any conflicts.

git fetch origin release-1.14
git worktree add -d .worktree/backport-5353-to-release-1.14 origin/release-1.14
cd .worktree/backport-5353-to-release-1.14
git switch --create backport-5353-to-release-1.14
git cherry-pick -x f3f5ece2f65afc19ea8d16c88e5ef12889e8d813

[github-actions]

Successfully created backport PR for release-1.15:

• [Backport release-1.15] Do not use version when indexing Used resources in Usage Handler #5354