*: Allow Point_Get during DDL with Global Index

[mjonss]

What problem does this PR solve?

Issue Number: ref #55819 , ref #45133

Problem Summary: During DDL that affects Global Index, the PointGet access method is blocked, which may cause temporary bad query plans during partitioning management commands, like DROP/TRUNCATE/REORGANIZE PARTITION.

What changed and how does it work?

Allow PointGet, by filter away the partitions that should not be seen (like when the cleanup of the global index is ongoing).

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

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None