[cherry-pick]Add Job Service Dashboard Schedules testcase

[YangJiao0817]

Fix #17949

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Comprehensive Summary of your change

Issue being fixed

Fixes #(issue)

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[codecov]

Codecov Report

Merging #18556 (89cdbfd) into release-2.7.0 (0d6633e) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@                Coverage Diff                @@
##           release-2.7.0   #18556      +/-   ##
=================================================
- Coverage          66.40%   66.39%   -0.02%     
=================================================
  Files               1012     1012              
  Lines             108614   108614              
  Branches            2677     2677              
=================================================
- Hits               72128    72112      -16     
- Misses             32526    32539      +13     
- Partials            3960     3963       +3     

Flag	Coverage Δ
unittests	66.39% <ø> (-0.02%)	⬇️

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see 6 files with indirect coverage changes