enhance: Allow empty sparse row

[zhengbuqian]

issue: #29419

• If a sparse vector with 0 non-zero value is inserted, no ANN search on this sparse vector field will return it as a result. User may retrieve this row via scalar query or ANN search on another vector field though.
• If the user uses an empty sparse vector as the query vector for a ANN search, no neighbor will be returned.

[mergify]

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

[zhengbuqian]

/hold

[zhengbuqian]

/unhold

[mergify]

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

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.81%. Comparing base (c61592d) to head (c0862ba).
Report is 204 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #34700      +/-   ##
==========================================
- Coverage   84.44%   80.81%   -3.63%     
==========================================
  Files         892     1157     +265     
  Lines      117014   141659   +24645     
==========================================
+ Hits        98807   114477   +15670     
- Misses      13836    22813    +8977     
+ Partials     4371     4369       -2     

Files	Coverage Δ
internal/core/src/common/Utils.h	89.62% <ø> (ø)
internal/core/src/segcore/FieldIndexing.h	67.25% <100.00%> (ø)
pkg/util/typeutil/schema.go	85.92% <100.00%> (+0.14%)	⬆️

... and 296 files with indirect coverage changes

[wangyiran33]

hope this feature continues to progress; it's very much needed～～～～

[czs007]

/approve
/lgtm

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

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

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