*: use another etcd client for election (#6409)

[ti-chi-bot]

This is an automated cherry-pick of #6409

What problem does this PR solve?

Issue Number: Ref #6403.

What is changed and how does it work?

This PR tries to use another etcd client for the election to prevent the throttling of one connection.

Check List

Tests

• Manual test (TODO)

Release note

None.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• nolouch

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[codecov]

Codecov Report

Patch coverage: 50.00% and project coverage change: -0.04 ⚠️

Comparison is base (10b691a) 75.67% compared to head (94a0307) 75.64%.

Additional details and impacted files

@@               Coverage Diff               @@
##           release-6.5    #6454      +/-   ##
===============================================
- Coverage        75.67%   75.64%   -0.04%     
===============================================
  Files              330      330              
  Lines            33009    33023      +14     
===============================================
  Hits             24980    24980              
  Misses            5882     5882              
- Partials          2147     2161      +14     

Flag	Coverage Δ
unittests	75.64% <50.00%> (-0.04%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
server/server.go	74.57% <50.00%> (-1.18%)	⬇️

... and 28 files with indirect coverage changes

☔ View full report in Codecov by Sentry.
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[rleungx]

@nolouch PTAL

[nolouch]

/merge

[ti-chi-bot]

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

/run-all-tests

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[ti-chi-bot]

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

Details

Commit hash: 94a0307

[ti-chi-bot]

@ti-chi-bot: Your PR was out of date, I have automatically updated it for you.

If the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

Details

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.