feature: clean up the use of fake clients

[stevekuznetsov]

This is not strictly necessary but a very nice to have for #1943

• [x] pkg/admission/namespacelifecycle/admission_test.go: "k8s.io/client-go/kubernetes/fake" @ncdc (https://github.com/kcp-dev/kcp/pull/2162)
• [ ] pkg/authorization/workspace_content_authorizer_test.go: kubefake "k8s.io/client-go/kubernetes/fake"
• [x] pkg/client/clientset/versioned/fake/clientset_generated.go: fakediscovery "k8s.io/client-go/discovery/fake"
• [x] pkg/crdpuller/discovery_test.go: "k8s.io/apiextensions-apiserver/pkg/client/clientset/clientset/fake" @ncdc (https://github.com/kcp-dev/kcp/pull/2163)
• [x] pkg/reconciler/apis/apibindingdeletion/apibinding_deletor_test.go: metadatafake "k8s.io/client-go/metadata/fake" @stevekuznetsov (https://github.com/kcp-dev/kcp/pull/2173)
• [x] pkg/reconciler/apis/identitycache/api_export_identity_reconcile_test.go: "k8s.io/client-go/kubernetes/fake" @stevekuznetsov (https://github.com/kcp-dev/kcp/pull/2168)
• [ ] pkg/reconciler/cache/replication/replication_reconcile_apiexports_test.go: dynamicfake "k8s.io/client-go/dynamic/fake" @stevekuznetsov (https://github.com/kcp-dev/kcp/pull/2170)
• [ ] pkg/reconciler/cache/replication/replication_reconcile_unstructured_test.go: dynamicfake "k8s.io/client-go/dynamic/fake" @stevekuznetsov (https://github.com/kcp-dev/kcp/pull/2170)
• [ ] pkg/reconciler/tenancy/clusterworkspacedeletion/deletion/workspace_resource_deletor_test.go: metadatafake "k8s.io/client-go/metadata/fake"
• [ ] pkg/syncer/spec/spec_process_test.go: dynamicfake "k8s.io/client-go/dynamic/fake"
• [ ] pkg/syncer/status/status_process_test.go: dynamicfake "k8s.io/client-go/dynamic/fake"
• [ ] pkg/virtual/framework/forwardingregistry/rest_test.go: "k8s.io/client-go/dynamic/fake"
• [ ] pkg/virtual/workspaces/authorization/cache_test.go: "k8s.io/client-go/kubernetes/fake"
• [ ] pkg/virtual/workspaces/registry/rest_test.go: "k8s.io/client-go/kubernetes/fake"
• [x] test/e2e/fixtures/wildwest/client/clientset/versioned/fake/clientset_generated.go: fakediscovery "k8s.io/client-go/discovery/fake"

[kcp-ci-bot]

Issues go stale after 90d of inactivity. After a furter 30 days, they will turn rotten. Mark the issue as fresh with /remove-lifecycle stale.

If this issue is safe to close now please do so with /close.

/lifecycle stale

[kcp-ci-bot]

Stale issues rot after 30d of inactivity. Mark the issue as fresh with /remove-lifecycle rotten. Rotten issues close after an additional 30d of inactivity.

If this issue is safe to close now please do so with /close.

/lifecycle rotten

[kcp-ci-bot]

Rotten issues close after 30d of inactivity. Reopen the issue with /reopen. Mark the issue as fresh with /remove-lifecycle rotten.

/close

[kcp-ci-bot]

@kcp-ci-bot: Closing this issue.

In response to [this](https://github.com/kcp-dev/kcp/issues/2167#issuecomment-2166713901): >Rotten issues close after 30d of inactivity. >Reopen the issue with `/reopen`. >Mark the issue as fresh with `/remove-lifecycle rotten`. > >/close Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository.