cleanup: enable revive(var-declaration rule) checking

[jwcesign]

What type of PR is this?
/kind cleanup

What this PR does / why we need it:
cleanup: enable revive(var-declaration rule) checking

Which issue(s) this PR fixes:
Part of #4490

Special notes for your reviewer:
none

Does this PR introduce a user-facing change?:

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (830f652) 51.86% compared to head (367db18) 51.87%.
Report is 2 commits behind head on master.

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Additional details and impacted files

@@           Coverage Diff           @@
##           master    #4492   +/-   ##
=======================================
  Coverage   51.86%   51.87%           
=======================================
  Files         243      243           
  Lines       24183    24183           
=======================================
+ Hits        12543    12544    +1     
+ Misses      10958    10957    -1     
  Partials      682      682           

Flag	Coverage Δ
unittests	51.87% <ø> (+<0.01%)	⬆️

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[RainbowMango]

You might need to resolve the conflict.
LGTM.

[RainbowMango]

conflict again.

[RainbowMango]

/lgtm
/approve

[karmada-bot]

[APPROVALNOTIFIER] This PR is APPROVED

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