chore: unify karmada labels/annotations usage in execution controller and test

[a7i]

What type of PR is this?

/kind cleanup

What this PR does / why we need it:
So we don't manage them in two different places and end up missing updating one

Which issue(s) this PR fixes:
None

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

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Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 41.66%. Comparing base (1cd75f4) to head (1a7409d).

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Additional details and impacted files

@@           Coverage Diff           @@
##           master    #5747   +/-   ##
=======================================
  Coverage   41.65%   41.66%           
=======================================
  Files         653      653           
  Lines       55533    55518   -15     
=======================================
- Hits        23135    23132    -3     
+ Misses      30894    30885    -9     
+ Partials     1504     1501    -3     

Flag	Coverage Δ
unittests	41.66% <100.00%> (+<0.01%)	⬆️

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[chaosi-zju]

pretty clean code, thanks

/lgtm

[XiShanYongYe-Chang]

Thanks a lot~
/approve

[karmada-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: XiShanYongYe-Chang

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Needs approval from an approver in each of these files:

• pkg/controllers/OWNERS [XiShanYongYe-Chang]
• pkg/util/OWNERS [XiShanYongYe-Chang]
• test/OWNERS [XiShanYongYe-Chang]

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