fix: fix empty indices of sparse float

[sunby]

https://github.com/milvus-io/milvus/issues/35401

[mergify[bot]]

@sunby Please associate the related issue to the body of your Pull Request. (eg. “issue: #”)

[czs007]

/approve /lgtm

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: czs007, sunby

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[mergify[bot]]

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

[sunby]

rerun go-sdk

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 72.63%. Comparing base (5aedc16) to head (6fd5c11). Report is 5 commits behind head on master.

Files with missing lines	Patch %	Lines
internal/core/src/mmap/Utils.h	0.00%	1 Missing :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #35403      +/-   ##
==========================================
- Coverage   81.60%   72.63%   -8.98%     
==========================================
  Files        1268     1268              
  Lines      151077   151078       +1     
==========================================
- Hits       123283   109728   -13555     
- Misses      22895    36452   +13557     
+ Partials     4899     4898       -1     

Files with missing lines	Coverage Δ
internal/core/src/mmap/Utils.h	0.00% <0.00%> (-71.24%)	:arrow_down:

... and 236 files with indirect coverage changes

[czs007]

/lgtm