fix: Cherry pick of #1669 for release-3.7: Allow mutation to run as a standalone pod

[sozercan]

What this PR does / why we need it:
Cherry pick of #1669 for release 3.7

Which issue(s) this PR fixes (optional, using fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when the PR gets merged):
Fixes #

Special notes for your reviewer:

[codecov-commenter]

Codecov Report

Merging #1813 (4cf6020) into release-3.7 (3ba8e93) will decrease coverage by 0.30%.
The diff coverage is 0.00%.

@@               Coverage Diff               @@
##           release-3.7    #1813      +/-   ##
===============================================
- Coverage        52.17%   51.87%   -0.31%     
===============================================
  Files               98       98              
  Lines             8693     8704      +11     
===============================================
- Hits              4536     4515      -21     
- Misses            3798     3827      +29     
- Partials           359      362       +3     

Flag	Coverage Δ
unittests	51.87% <0.00%> (-0.31%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
pkg/webhook/policy.go	28.93% <0.00%> (-0.93%)	⬇️
...onstrainttemplate/constrainttemplate_controller.go	55.45% <0.00%> (-4.98%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3ba8e93...4cf6020. Read the comment docs.

[maxsmythe]

LGTM