enhance: [2.5] Limit the speed of the generating stats task

[xiaocai2333]

master pr: #39644

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[codecov]

Codecov Report

Attention: Patch coverage is 87.50000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 80.97%. Comparing base (22a69b5) to head (7dc87bf).
Report is 1 commits behind head on 2.5.

Files with missing lines	Patch %	Lines
internal/datacoord/job_manager.go	0.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              2.5   #39645      +/-   ##
==========================================
- Coverage   80.99%   80.97%   -0.02%     
==========================================
  Files        1404     1404              
  Lines      198042   198057      +15     
==========================================
- Hits       160409   160383      -26     
- Misses      32002    32031      +29     
- Partials     5631     5643      +12     

Components	Coverage Δ
Client	78.26% <ø> (ø)
Core	69.48% <ø> (-0.02%)	⬇️
Go	82.94% <87.50%> (-0.03%)	⬇️

Files with missing lines	Coverage Δ
internal/datacoord/task_scheduler.go	95.84% <100.00%> (+0.04%)	⬆️
pkg/util/paramtable/component_param.go	98.40% <100.00%> (+<0.01%)	⬆️
internal/datacoord/job_manager.go	73.15% <0.00%> (-3.57%)	⬇️

... and 32 files with indirect coverage changes