enhance:[2.4] return topks when search in restful v2

[smellthemoon]

pr: #39812
2.5: #39839

[mergify]

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

[czs007]

/approve
/lgtm

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

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

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[codecov]

Codecov Report

Attention: Patch coverage is 66.66667% with 1 line in your changes missing coverage. Please review.

Project coverage is 70.41%. Comparing base (c9c9ef9) to head (daefff0).
Report is 2 commits behind head on 2.4.

Files with missing lines	Patch %	Lines
...nternal/distributed/proxy/httpserver/handler_v2.go	66.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              2.4   #39858      +/-   ##
==========================================
- Coverage   80.36%   70.41%   -9.96%     
==========================================
  Files        1081     1081              
  Lines      170442   170448       +6     
==========================================
- Hits       136968   120013   -16955     
- Misses      28949    45916   +16967     
+ Partials     4525     4519       -6     

Files with missing lines	Coverage Δ
...nternal/distributed/proxy/httpserver/handler_v2.go	91.82% <66.66%> (ø)

... and 267 files with indirect coverage changes