Issue 7068: add a finalizer to protect retained VSC

[Lyndon-Li]

Fix issue #7068, due to a behavior of CSI external snapshotter, manipulations of VS and VSC may not be handled in the same order inside external snapshotter as the API is called. So add a protection finalizer to ensure the order

[codecov]

Codecov Report

Attention: 9 lines in your changes are missing coverage. Please review.

Comparison is base (e826b70) 61.22% compared to head (cb651d0) 61.23%.

Files	Patch %	Lines
pkg/util/csi/volume_snapshot.go	75.00%	6 Missing and 3 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7095      +/-   ##
==========================================
+ Coverage   61.22%   61.23%   +0.01%     
==========================================
  Files         257      257              
  Lines       27259    27272      +13     
==========================================
+ Hits        16688    16701      +13     
  Misses       9388     9388              
  Partials     1183     1183              

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