Fix: PVC finalizer not removed due to broken VolumeSnapshots

[vasumahalingam-nutanix]

What type of PR is this?

/kind bug

What this PR does / why we need it:

Fixes a bug where a PVC’s finalizer snapshot.storage.kubernetes.io/pvc-as-source-protection is not removed when there are broken or misconfigured VolumeSnapshots that reference the PVC but never transition to ReadyToUse.

The snapshot controller currently considers any VolumeSnapshot with ReadyToUse == false as blocking PVC deletion — even if the snapshot is invalid and has already failed.

This patch ensures the controller only considers:

• VolumeSnapshots with ReadyToUse == false, and
• that still retain the pvc-as-source-protection finalizer

This avoids permanently stuck PVCs when broken snapshots linger in the namespace.

Which issue(s) this PR fixes:
Fixes #1305

Special notes for your reviewer:

• The change preserves the protective behavior for in-progress snapshots.
• The PVC can now be deleted once only broken snapshots remain, and they no longer hold the finalizer.

Does this PR introduce a user-facing change?:

release-note Fix: PVC finalizer `snapshot.storage.kubernetes.io/pvc-as-source-protection` is now removed even if other VolumeSnapshots are stuck in a failed state, as long as those snapshots no longer hold the finalizer.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: vasumahalingam-nutanix
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[k8s-ci-robot]

Hi @vasumahalingam-nutanix. Thanks for your PR.

I'm waiting for a kubernetes-csi 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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[vasumahalingam-nutanix]

Hi @gnufied , @sunnylovestiramisu PTAL when you get a chance. This PR resolves an edge case where PVC deletion is blocked due to broken VolumeSnapshots that are no longer usable or hold the finalizer. It ensures correctness without affecting valid in-progress snapshots. Thanks!