CSI doc change and remove the CSI feature verifier

[blackpiglet]

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Please add a summary of your change

Does your change fix a particular issue?

Fixes #7651

Please indicate you've done the following:

• Accepted the DCO. Commits without the DCO will delay acceptance.
• Created a changelog file or added /kind changelog-not-required as a comment on this pull request.
• Updated the corresponding documentation in site/content/docs/main.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 13 lines in your changes are missing coverage. Please review.

Project coverage is 61.82%. Comparing base (f25c154) to head (59eeec2).
Report is 4 commits behind head on main.

Files	Patch %	Lines
pkg/backup/actions/csi/volumesnapshot_action.go	0.00%	8 Missing ⚠️
pkg/restore/actions/csi/volumesnapshot_action.go	0.00%	3 Missing ⚠️
...estore/actions/csi/volumesnapshotcontent_action.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7656      +/-   ##
==========================================
+ Coverage   61.26%   61.82%   +0.55%     
==========================================
  Files         276      276              
  Lines       31338    24864    -6474     
==========================================
- Hits        19200    15371    -3829     
+ Misses      10784     8134    -2650     
- Partials     1354     1359       +5     

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