*: fix sync isolation level to default placement rule

[rleungx]

What problem does this PR solve?

Issue Number: Close #7121.

What is changed and how does it work?

This PR will sync the isolation level to the default rule when setting config with HTTP API or pd-ctl.

Check List

Tests

• Unit test

Release note

None.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• JmPotato
• bufferflies

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[codecov]

Codecov Report

Merging #7122 (2bf92ca) into master (a997316) will increase coverage by 0.05%.
Report is 1 commits behind head on master.
The diff coverage is 78.57%.

❗ Current head 2bf92ca differs from pull request most recent head 5e123e2. Consider uploading reports for the commit 5e123e2 to get more accurate results

@@            Coverage Diff             @@
##           master    #7122      +/-   ##
==========================================
+ Coverage   74.32%   74.37%   +0.05%     
==========================================
  Files         440      440              
  Lines       47195    47157      -38     
==========================================
- Hits        35076    35073       -3     
+ Misses       9024     8997      -27     
+ Partials     3095     3087       -8     

Flag	Coverage Δ
unittests	74.37% <78.57%> (+0.05%)	⬆️

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

[JmPotato]

What if we update the isolation-level? Will it be set to the rule also?

[rleungx]

What if we update the isolation-level? Will it be set to the rule also?

Do you mean TestUpdateDefaultReplicaConfig?

[JmPotato]

/merge

[ti-chi-bot]

@JmPotato: 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.

Commit hash: 2bf92ca

[ti-chi-bot]

@rleungx: Your PR was out of date, I have automatically updated it for you.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.

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[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-5.3: #7123.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-5.4: #7124.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.1: #7125.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.5: #7126.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.1: #7127.