fix: clean up metrics for deleted mvtx

[whynowy]

Closes: #2336

1. Clean up mvtx related metrics with best effort
2. Always use finalizer for ISBSvc regardless of pvc used or not, so that it can be used to do all the clean up.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 67.58%. Comparing base (d544908) to head (206c4f4).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2338      +/-   ##
==========================================
+ Coverage   67.48%   67.58%   +0.09%     
==========================================
  Files         351      351              
  Lines       45929    45924       -5     
==========================================
+ Hits        30994    31036      +42     
+ Misses      13860    13807      -53     
- Partials     1075     1081       +6     

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