metrics: fix wrong value in the sync load QPS (#53559)

[ti-chi-bot]

This is an automated cherry-pick of #53559

What problem does this PR solve?

Issue Number: close #53558

Problem Summary:

What changed and how does it work?

Sync load's QPS in the grafana should be integer.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)

before

after

• 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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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-05-27 07:11:26.180279846 +0000 UTC m=+2674039.937415418: ☑️ agreed by hawkingrei.
• 2024-05-27 07:12:00.00197116 +0000 UTC m=+2674073.759106745: ☑️ agreed by AilinKid.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Please upload report for BASE (release-7.5@f3f5b69). Learn more about missing BASE report.

Additional details and impacted files

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Flag	Coverage Δ
unit	72.0733% <ø> (?)

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