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

• [x] 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[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

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

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files: - ~~[pkg/statistics/OWNERS](https://github.com/pingcap/tidb/blob/release-8.5/pkg/statistics/OWNERS)~~ [AilinKid,hawkingrei] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[ti-chi-bot[bot]]

[LGTM Timeline notifier]

Timeline:

• 2024-11-20 09:57:23.742810774 +0000 UTC m=+25631.362465284: :ballot_box_with_check: agreed by hawkingrei.
• 2024-11-20 09:59:34.628088059 +0000 UTC m=+25762.247742575: :ballot_box_with_check: agreed by AilinKid.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Please upload report for BASE (release-8.5@5cf2682). Learn more about missing BASE report.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## release-8.5 #57559 +/- ## ================================================ Coverage ? 57.0304% ================================================ Files ? 1770 Lines ? 628036 Branches ? 0 ================================================ Hits ? 358172 Misses ? 245916 Partials ? 23948 ``` | [Flag](https://app.codecov.io/gh/pingcap/tidb/pull/57559/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | Coverage Δ | | |---|---|---| | [integration](https://app.codecov.io/gh/pingcap/tidb/pull/57559/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `36.9171% <100.0000%> (?)` | | | [unit](https://app.codecov.io/gh/pingcap/tidb/pull/57559/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `72.7474% <90.0000%> (?)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap#carryforward-flags-in-the-pull-request-comment) to find out more. | [Components](https://app.codecov.io/gh/pingcap/tidb/pull/57559/components?src=pr&el=components&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | Coverage Δ | | |---|---|---| | [dumpling](https://app.codecov.io/gh/pingcap/tidb/pull/57559/components?src=pr&el=component&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `52.9478% <0.0000%> (?)` | | | [parser](https://app.codecov.io/gh/pingcap/tidb/pull/57559/components?src=pr&el=component&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `∅ <0.0000%> (?)` | | | [br](https://app.codecov.io/gh/pingcap/tidb/pull/57559/components?src=pr&el=component&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `52.3192% <0.0000%> (?)` | |

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[hawkingrei]

/retest