fix: improve error handling for discarded hooks in WaitExecHookHandler

[priyansh17]

Signed-off-by: Priyansh Choudhary im1706@gmail.com

Thank you for contributing to Velero!

Please add a summary of your change

The early-return in HandleHooks (when byContainer empty or pod==nil) should Record(... hookFailed=true ...) in the multiHookTracker, or else never Add such hooks in the first place. Otherwise, tracker cannot complete, and the restore gets stuck forever.

Does your change fix a particular issue?

Yes
Fixes #(issue)
#9749

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

❌ Patch coverage is 19.04762% with 17 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
internal/hook/wait_exec_hook_handler.go	10.52%	17 Missing ⚠️

📢 Thoughts on this report? Let us know!