fix: fail backup early when CSI VolumeSnapshot error persists in async poll

[priyansh17]

Please add a summary of your change

• This bug can be reproduced by triggering a scenario where cloud snapshot provisioning fails (e.g., make Azure Disk run out of available capacity or permissions).
• The problematic code path is in pkg/backup/actions/csi/volumesnapshot_action.go, in the Progress() method of volumeSnapshotBackupItemAction:

if boolptr.IsSetToTrue(vs.Status.ReadyToUse) {
    // ... continue to check VSC
} else if vs.Status.Error != nil {
    errorMessage := ""
    if vs.Status.Error.Message != nil {
        errorMessage = *vs.Status.Error.Message
    }
    p.log.Warnf("VolumeSnapshot has a temporary error %s. Snapshot controller will retry later.", errorMessage)
    return progress, nil  // <-- Returns NOT completed, no error propagated
}

• This returns progress.Completed=false even for permanent errors, so the backup controller keeps polling Progress() for the full itemOperationTimeout (could be hours), instead of failing immediately.
• The synchronous code path (WaitUntilVSCHandleIsReady) properly fails on timeout, but async Progress() does not.

The fix is to wait for a certain period of time before failing it/ skipping it.

Does your change fix a particular issue?

Fixes #(issue)
#9674

Please indicate you've done the following:

• Accepted the DCO. Commits without the DCO will delay acceptance.
• Created a changelog file (make new-changelog) or comment /kind changelog-not-required on this PR.
• Updated the corresponding documentation in site/content/docs/main.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 61.00%. Comparing base (c5fa50b) to head (a6256ae).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9727      +/-   ##
==========================================
+ Coverage   60.97%   61.00%   +0.02%     
==========================================
  Files         384      384              
  Lines       36609    36629      +20     
==========================================
+ Hits        22324    22344      +20     
  Misses      12677    12677              
  Partials     1608     1608              

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