coordinator, mcs/scheduling: fix the default schedulers initialization

[JmPotato]

What problem does this PR solve?

Issue Number: close #7169.

What is changed and how does it work?

Fix the default scheduler initialization of the scheduling service.

Check List

Tests

• Unit test
• Integration test

Release note

None.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• lhy1024
• rleungx

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[codecov]

Codecov Report

Merging #7236 (5359c9c) into master (8b2896b) will decrease coverage by 0.25%.
Report is 6 commits behind head on master.
The diff coverage is 37.60%.

@@            Coverage Diff             @@
##           master    #7236      +/-   ##
==========================================
- Coverage   74.65%   74.40%   -0.25%     
==========================================
  Files         442      442              
  Lines       47744    48026     +282     
==========================================
+ Hits        35642    35733      +91     
- Misses       8957     9139     +182     
- Partials     3145     3154       +9     

Flag	Coverage Δ
unittests	74.40% <37.60%> (-0.25%)	⬇️

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[JmPotato]

/merge

[ti-chi-bot]

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[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 5359c9c