Automated cherry pick of #5012: Account for unschedulable plugin result during maxreplica

[RainbowMango]

Cherry pick of #5012 on release-1.10.
#5012: Account for unschedulable plugin result during maxreplica
For details on the cherry pick process, see the cherry pick requests page.

`karmada-scheduler-estimator`: Fixed the `Unschedulable` result returned by plugins to be treated as an exception issue.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 62.50000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 53.30%. Comparing base (c181917) to head (185770a).

Files	Patch %	Lines
pkg/estimator/server/estimate.go	0.00%	1 Missing and 1 partial ⚠️
pkg/scheduler/core/util.go	80.00%	1 Missing ⚠️

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Additional details and impacted files

@@               Coverage Diff                @@
##           release-1.10    #5027      +/-   ##
================================================
- Coverage         53.32%   53.30%   -0.03%     
================================================
  Files               253      253              
  Lines             20560    20565       +5     
================================================
- Hits              10964    10962       -2     
- Misses             8870     8876       +6     
- Partials            726      727       +1     

Flag	Coverage Δ
unittests	53.30% <62.50%> (-0.03%)	⬇️

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[karmada-bot]

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