statstics: fix wrong stats health metrics (#57555)

[ti-chi-bot]

This is an automated cherry-pick of #57555

What problem does this PR solve?

Issue Number: close #57176

Problem Summary:

What changed and how does it work?

we use the wrong index of total table count metrics.

Check List

Tests

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

  • I checked and no code files have been changed.

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

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: AilinKid, hawkingrei

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• pkg/statistics/OWNERS [AilinKid,hawkingrei]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-11-29 06:36:24.089100193 +0000 UTC m=+791171.708754710: ☑️ agreed by hawkingrei.
• 2024-11-29 06:37:48.980046804 +0000 UTC m=+791256.599701320: ☑️ agreed by AilinKid.

[hawkingrei]

/retest

[codecov]

Codecov Report

Attention: Patch coverage is 90.00000% with 1 line in your changes missing coverage. Please review.

Please upload report for BASE (release-7.5@f4f11b5). Learn more about missing BASE report.

Additional details and impacted files

@@               Coverage Diff                @@
##             release-7.5     #57830   +/-   ##
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  Coverage               ?   72.1646%           
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Flag	Coverage Δ
unit	72.1646% <90.0000%> (?)

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

Components	Coverage Δ
dumpling	52.9400% <0.0000%> (?)
parser	∅ <0.0000%> (?)
br	53.5383% <0.0000%> (?)