server/api: add the api to show the regions in subtree by type

[nolouch]

What problem does this PR solve?

Issue Number: Close #8100

What is changed and how does it work?

server/api: add the api to show the regions in subtree by type

Check List

Tests

• Unit test

Release note

None.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• JmPotato
• rleungx

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[codecov]

Codecov Report

Attention: Patch coverage is 71.79487% with 11 lines in your changes are missing coverage. Please review.

Project coverage is 77.39%. Comparing base (aae410f) to head (9d2f12b).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #8101      +/-   ##
==========================================
- Coverage   77.40%   77.39%   -0.01%     
==========================================
  Files         471      471              
  Lines       61257    61295      +38     
==========================================
+ Hits        47416    47440      +24     
- Misses      10284    10295      +11     
- Partials     3557     3560       +3     

Flag	Coverage Δ
unittests	77.39% <71.79%> (-0.01%)	⬇️

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[JmPotato]

/merge

[ti-chi-bot]

@JmPotato: It seems you want to merge this PR, I will help you trigger all the tests:

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[ti-chi-bot]

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

Commit hash: 74c0424