perf: optimize the trigger retention API

[chlins]

Enhance the API for triggering retention by optimizing it from synchronous to asynchronous to solve the problem of slow response in the case of a large number of tasks.

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Comprehensive Summary of your change

Issue being fixed

Fixes #18504

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• Well Written Title and Summary of the PR
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• Made sure tests are passing and test coverage is added if needed.
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[codecov]

Codecov Report

Merging #19533 (9c9f440) into main (b7116ff) will increase coverage by 0.02%.
The diff coverage is 41.17%.

@@            Coverage Diff             @@
##             main   #19533      +/-   ##
==========================================
+ Coverage   67.53%   67.55%   +0.02%     
==========================================
  Files         990      990              
  Lines      108998   109021      +23     
  Branches     2719     2719              
==========================================
+ Hits        73612    73653      +41     
+ Misses      31424    31402      -22     
- Partials     3962     3966       +4     

Flag	Coverage Δ
unittests	67.55% <41.17%> (+0.02%)	⬆️

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Files	Coverage Δ
src/controller/retention/controller.go	47.01% <41.17%> (+0.45%)	⬆️

... and 8 files with indirect coverage changes