enhance: make delegator lock critical smaller

[chyezh]

issue: #36804

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 72.35%. Comparing base (8669153) to head (0d5be22).
Report is 6 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #36997      +/-   ##
==========================================
- Coverage   80.64%   72.35%   -8.30%     
==========================================
  Files        1310     1310              
  Lines      183578   183597      +19     
==========================================
- Hits       148054   132848   -15206     
- Misses      30393    45635   +15242     
+ Partials     5131     5114      -17     

Files with missing lines	Coverage Δ
internal/querynodev2/delegator/delegator_data.go	85.54% <100.00%> (-0.92%)	⬇️

... and 244 files with indirect coverage changes

[weiliu1031]

/lgtm

[czs007]

/approve

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

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