Refactor pod volume context

[Lyndon-Li]

Refactor pod volume context code to avoid misuse of podVolumeTimeout which is integrated to a context with a general name ctx

[codecov]

Codecov Report

Attention: Patch coverage is 92.30769% with 1 line in your changes missing coverage. Please review.

Project coverage is 59.37%. Comparing base (294bbbc) to head (de17004).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/backup/backup.go	88.88%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8664      +/-   ##
==========================================
- Coverage   59.39%   59.37%   -0.02%     
==========================================
  Files         370      370              
  Lines       39987    39989       +2     
==========================================
- Hits        23750    23744       -6     
- Misses      14745    14752       +7     
- Partials     1492     1493       +1     

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