fix: fix alter collection failed for STRUCT sub-fields

[SpadeA-Tang]

issue: #45001
ref: #42148

[sre-ci-robot]

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[codecov]

Codecov Report

❌ Patch coverage is 0% with 17 lines in your changes missing coverage. Please review.
✅ Project coverage is 76.93%. Comparing base (cab9ee6) to head (1abc84a).
⚠️ Report is 10 commits behind head on master.

Files with missing lines	Patch %	Lines
internal/rootcoord/alter_collection_task.go	0.00%	16 Missing and 1 partial ⚠️

❌ Your patch status has failed because the patch coverage (0.00%) is below the target coverage (80.00%). You can increase the patch coverage or adjust the target coverage.
❌ Your project status has failed because the head coverage (76.93%) is below the target coverage (77.00%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #45041      +/-   ##
==========================================
+ Coverage   74.35%   76.93%   +2.58%     
==========================================
  Files        1331     1838     +507     
  Lines      207555   285520   +77965     
==========================================
+ Hits       154318   219657   +65339     
- Misses      46033    58651   +12618     
- Partials     7204     7212       +8     

Components	Coverage Δ
Client	78.03% <ø> (ø)
Core	83.88% <ø> (∅)
Go	75.03% <0.00%> (-0.04%)	⬇️

Files with missing lines	Coverage Δ
internal/rootcoord/alter_collection_task.go	80.24% <0.00%> (-4.45%)	⬇️

... and 530 files with indirect coverage changes

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[sre-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: SpadeA-Tang, zhengbuqian

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• internal/rootcoord/OWNERS [zhengbuqian]

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[SpadeA-Tang]

/ci-rerun-ut-go

[SpadeA-Tang]

/ci-rerun-ut-go

[SpadeA-Tang]

/ci-rerun-ut-go

[zhagnlu]

/lgtm