enhance: remove cooling off in rate limiter for read requests

[jaime0815]

issue: #35934
pr: #35935

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.13%. Comparing base (55df253) to head (78089e6).
Report is 4 commits behind head on 2.4.

Additional details and impacted files

@@            Coverage Diff             @@
##              2.4   #35936      +/-   ##
==========================================
- Coverage   81.16%   81.13%   -0.04%     
==========================================
  Files        1056     1056              
  Lines      139414   139059     -355     
==========================================
- Hits       113161   112824     -337     
- Misses      21958    21959       +1     
+ Partials     4295     4276      -19     

Files with missing lines	Coverage Δ
internal/proxy/impl.go	85.96% <ø> (-0.04%)	⬇️
internal/proxy/metrics_info.go	88.56% <ø> (-0.08%)	⬇️
internal/proxy/proxy.go	70.22% <ø> (-0.12%)	⬇️
internal/querynodev2/collector/collector.go	84.61% <ø> (-8.25%)	⬇️
internal/querynodev2/metrics_info.go	86.48% <ø> (+2.04%)	⬆️
internal/querynodev2/services.go	91.50% <ø> (+0.37%)	⬆️
internal/querynodev2/tasks/query_task.go	91.75% <ø> (-0.09%)	⬇️
internal/querynodev2/tasks/search_task.go	85.64% <ø> (-0.04%)	⬇️
internal/rootcoord/quota_center.go	86.49% <ø> (+0.98%)	⬆️
pkg/util/paramtable/quota_param.go	79.03% <ø> (-1.20%)	⬇️

... and 31 files with indirect coverage changes

[bigsheeper]

/lgtm

[czs007]

/approve
/lgtm

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: czs007, jaime0815

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Needs approval from an approver in each of these files:

• configs/OWNERS [czs007]
• internal/proxy/OWNERS [czs007]
• internal/querynodev2/OWNERS [czs007]
• internal/rootcoord/OWNERS [czs007]
• pkg/util/OWNERS [czs007]

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