fix: [2.5] Skip erase field if index build on PK field

[congqixia]

Cherry pick from master
pr: #39370
Related to #39339

[mergify]

@congqixia go-sdk check failed, comment rerun go-sdk can trigger the job again.

[mergify]

@congqixia E2e jenkins job failed, comment /run-cpu-e2e can trigger the job again.

[mergify]

@congqixia cpp-unit-test check failed, comment rerun cpp-unit-test can trigger the job again.

[liliu-z]

/lgtm
/approve

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: congqixia, liliu-z

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[codecov]

Codecov Report

Attention: Patch coverage is 75.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 81.01%. Comparing base (e68d161) to head (2210e67).
Report is 10 commits behind head on 2.5.

Files with missing lines	Patch %	Lines
...rnal/core/src/segcore/ChunkedSegmentSealedImpl.cpp	50.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##              2.5   #39371       +/-   ##
===========================================
+ Coverage   69.50%   81.01%   +11.50%     
===========================================
  Files         300     1404     +1104     
  Lines       26763   197533   +170770     
===========================================
+ Hits        18602   160034   +141432     
- Misses       8161    31876    +23715     
- Partials        0     5623     +5623     

Components	Coverage Δ
Client	78.26% <ø> (∅)
Core	69.50% <75.00%> (+<0.01%)	⬆️
Go	82.98% <ø> (∅)

Files with missing lines	Coverage Δ
internal/core/src/segcore/SegmentSealedImpl.cpp	84.05% <100.00%> (+0.03%)	⬆️
...rnal/core/src/segcore/ChunkedSegmentSealedImpl.cpp	22.93% <50.00%> (+0.07%)	⬆️

... and 1105 files with indirect coverage changes

[congqixia]

/hold