Added tracking for deleted namespace status check in restore flow

[sangitaray2021]

Thank you for contributing to Velero!

Please add a summary of your change

Does your change fix a particular issue?

Fixes #8234

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.

[anshulahuja98]

For - #8234

[codecov]

Codecov Report

Attention: Patch coverage is 90.00000% with 4 lines in your changes missing coverage. Please review.

Project coverage is 59.23%. Comparing base (3f9c2dc) to head (963e878).
Report is 15 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/util/kube/namespace_deletionstatus_tracker.go	76.47%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8233      +/-   ##
==========================================
+ Coverage   59.15%   59.23%   +0.08%     
==========================================
  Files         367      368       +1     
  Lines       30777    30868      +91     
==========================================
+ Hits        18206    18285      +79     
- Misses      11113    11123      +10     
- Partials     1458     1460       +2     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[kaovilai]

Please add changelog and run linter.

[reasonerjt]

Given we've reached FC and this may impact the restore flow, let's hold this one until the branch is cut for v1.15

[anshulahuja98]

@kaovilai can you help review the PR?

[kaovilai]

IIUC from reviewing, this change reduce potential duplicate await on if namespace exists (wait for 10 min polling) to just one instance per restore. Is that correct?

It's not meant to add polling until deletion is complete to resume some other process?

[sangitaray2021]

IIUC from reviewing, this change reduce potential duplicate await on if namespace exists (wait for 10 min polling) to just one instance per restore. Is that correct?

It's not meant to add polling until deletion is complete to resume some other process?

yes thats correct. We are reducing duplicate wait by caching the namespace which is under deletion.

[kaovilai]

Why are there both ns and name parameters?
What purpose does that serve other than duplicate value params?

Is this interface meant to be more generic? Perhaps namespaceDeletionStatusTrackerKey(ns, name) was meant to be more like resourceDeletionStatusTrackerKey(kind, ns, name string) string ?