planner: return an error when meeting unexpected operator under UnionScan (#53956)

[ti-chi-bot]

This is an automated cherry-pick of #53956

What problem does this PR solve?

Issue Number: ref #53951

Problem Summary: planner: return an error when meeting unexpected operator under UnionScan

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.

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

[codecov]

Codecov Report

Attention: Patch coverage is 44.44444% with 5 lines in your changes missing coverage. Please review.

Please upload report for BASE (release-7.1@409465c). Learn more about missing BASE report.

Additional details and impacted files

@@               Coverage Diff                @@
##             release-7.1     #53969   +/-   ##
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  Coverage               ?   75.6399%           
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  Files                  ?       1212           
  Lines                  ?     402018           
  Branches               ?          0           
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  Hits                   ?     304086           
  Misses                 ?      80245           
  Partials               ?      17687           

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: AilinKid, hawkingrei, qw4990

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• OWNERS [AilinKid,hawkingrei,qw4990]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-11-05 08:14:38.587779758 +0000 UTC m=+942391.426935303: ☑️ agreed by AilinKid.
• 2024-11-11 02:39:56.967158243 +0000 UTC m=+237559.158027249: ☑️ agreed by qw4990.