✨ ClusterCache: Add GetUncachedClient()

[bnallapeta]

What this PR does / why we need it:

Adds GetUncachedClient method to the ClusterCache interface to support live (uncached) API calls to workload clusters. This helps reduce memory usage when you want to cache only a few types instead of having to exclude most types via DisableFor.
The uncached client is created alongside the cached one during connection setup and follows the same lifecycle (connect/disconnect).
Note: This introduces a breaking change to any existing implementations that are directly using ClusterCache.

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 #12784

/area controllers
/area clustercache

[k8s-ci-robot]

@bnallapeta: The label(s) area/controllers cannot be applied, because the repository doesn't have them.

In response to this:

What this PR does / why we need it:

• Introduces an optional extension interface to access a live (uncached) reader for workload clusters: UncachedReaderProvider with GetUncachedReader(ctx, cluster) (client.Reader, error)
• Wires a finalized uncached client into the connection lifecycle and exposes it via the accessor and a forwarder on clusterCache.
• Keeps existing ClusterCache API unchanged and fully backward compatible.

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 #12784

/area controllers
/area clustercache

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[k8s-ci-robot]

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[k8s-ci-robot]

Hi @bnallapeta. 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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[sbueringer]

/ok-to-test

[k8s-ci-robot]

@bnallapeta: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-cluster-api-apidiff-main	6f2d5be	link	false	/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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[bnallapeta]

@sbueringer I believe all the comments are addressed. Please take a look and let me know if there's anything else. Thank you.

[bnallapeta]

How do we handle the pull-cluster-api-apidiff-main that is failing? I get that its failing due to a API breaking change. But I could not find any file in the codebase where we can make it happy.

[sbueringer]

How do we handle the pull-cluster-api-apidiff-main that is failing? I get that its failing due to a API breaking change. But I could not find any file in the codebase where we can make it happy.

The job is optional for merge. It's just to highlight API differences to reviewers so they can make an informed choice if the change is acceptable (which it is in this case)

[sbueringer]

Thank you very much!

/lgtm
/approve

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 21efe23c4328518176f1bd00b5b58e3a968f7cc6

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: sbueringer

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