ci: delete the step for upgrade/downupgrade karmada-apiserver.

[liangyuanpeng]

• Add master branch to run workflow of karmada-apiserver compatibility.

What type of PR is this?

/kind cleanup
What this PR does / why we need it:

changes:

• delete the step for upgrade/downupgrade karmada-apiserver. (resolve the compatibility problem of karmada-apiserver downupgrade https://github.com/karmada-io/karmada/actions/runs/9734577204/job/26862782887 )
• Add master branch to run karmada-apiserver compatibility

cc @zhzhuang-zju

Tested on my fork repo: https://github.com/liangyuanpeng/karmada/actions/runs/9802951091
And reason of workflow is failing is have a test need to update for karmada-apiserver 1.30, it's working at #5141

Which issue(s) this PR fixes:
Fixes #

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 28.21%. Comparing base (c8acebc) to head (a422423).

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Additional details and impacted files

@@           Coverage Diff           @@
##           master    #5142   +/-   ##
=======================================
  Coverage   28.21%   28.21%           
=======================================
  Files         632      632           
  Lines       43568    43568           
=======================================
+ Hits        12291    12293    +2     
+ Misses      30381    30379    -2     
  Partials      896      896           

Flag	Coverage Δ
unittests	28.21% <ø> (+<0.01%)	⬆️

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[zhzhuang-zju]

/lgtm
/approve

[karmada-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: zhzhuang-zju

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