placement: fix alter meta range cannot work (#60889)

[ti-chi-bot]

This is an automated cherry-pick of #60889

What problem does this PR solve?

Issue Number: close #60888

Problem Summary:

What changed and how does it work?

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.

Release note

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None

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Please upload report for BASE (release-8.5@b957a04). Learn more about missing BASE report.

Additional details and impacted files

@@               Coverage Diff                @@
##             release-8.5     #61090   +/-   ##
================================================
  Coverage               ?   59.4836%           
================================================
  Files                  ?       1777           
  Lines                  ?     648071           
  Branches               ?          0           
================================================
  Hits                   ?     385496           
  Misses                 ?     238552           
  Partials               ?      24023           

Flag	Coverage Δ
integration	40.5010% <0.0000%> (?)
unit	74.6906% <100.0000%> (?)

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

Components	Coverage Δ
dumpling	52.9278% <0.0000%> (?)
parser	∅ <0.0000%> (?)
br	64.9397% <0.0000%> (?)

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[nolouch]

/retest-required

[nolouch]

/test unit-test

[tiprow]

@nolouch: No presubmit jobs available for pingcap/tidb@release-8.5

Details

In response to this:

/test unit-test

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-05-13 07:18:01.069708683 +0000 UTC m=+429547.217669902: ☑️ agreed by nolouch.
• 2025-05-19 02:32:57.335667272 +0000 UTC m=+339143.591564665: ☑️ agreed by rleungx.

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: nolouch, rleungx, tangenta

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[rleungx]

/retest