*: support show tiflash config

[solotzg]

What problem does this PR solve?

Issue Number: close #24252

What is changed and how it works?

What's Changed:

• support show tiflash config in INFORMATION_SCHEMA.CLUSTER_CONFIG and show config

How it Works:

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• ichn-hu
• lzmhhh123

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[solotzg]

@ichn-hu @lzmhhh123 PTAL

[solotzg]

/merge

[ti-chi-bot]

@solotzg: /merge is only allowed for the committers, you can assign this pull request to the committer in list by filling /assign @committer in the comment to help merge this pull request.

In response to this:

/merge

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[solotzg]

/assign @lzmhhh123

[ichn-hu]

/merge

[ti-chi-bot]

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

Commit hash: c3948e4