enhance: When describing an index, fetch the index info in batches

[xiaocai2333]

issue: #29313
master pr: #31238

[mergify]

@xiaocai2333 E2e jenkins job failed, comment /run-cpu-e2e can trigger the job again.

[codecov]

Codecov Report

Attention: Patch coverage is 88.23529% with 6 lines in your changes are missing coverage. Please review.

Project coverage is 82.21%. Comparing base (7105e0b) to head (fa77828).
Report is 8 commits behind head on 2.3.

Additional details and impacted files

@@            Coverage Diff             @@
##              2.3   #31239      +/-   ##
==========================================
- Coverage   82.24%   82.21%   -0.03%     
==========================================
  Files         844      844              
  Lines      122234   122258      +24     
==========================================
- Hits       100526   100518       -8     
- Misses      18480    18496      +16     
- Partials     3228     3244      +16     

Files	Coverage Δ
internal/datacoord/index_meta.go	98.13% <87.50%> (-0.42%)	⬇️
internal/datacoord/index_service.go	94.44% <88.88%> (-0.93%)	⬇️

... and 17 files with indirect coverage changes

[czs007]

/approve
/lgtm

[sre-ci-robot]

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