GH-53500: Guard Parquet metadata equality against None

[1932819331hy-debug]

Rationale for this change

Several Parquet metadata wrappers’ typed equals() methods can dereference None. Guard these arguments consistently with FileMetaData.equals() so explicit calls raise TypeError and comparisons with None are safe.

What changes are included in this PR?

• Reject None in Statistics, ColumnChunkMetaData, RowGroupMetaData, ParquetSchema, and ColumnSchema equals() methods.
• Add a regression test covering the five affected wrappers and FileMetaData.

Are these changes tested?

A regression test covers explicit equals(None) calls and != None comparisons. Tests were not run locally; GitHub CI will validate the Cython build and test.

Are there any user-facing changes?

Invalid equals(None) calls now raise TypeError instead of risking a process crash. Equality comparisons with None remain safe.

Was AI used for this PR?

PR code and description written by:

• AI

Reviewed before submission by:

• AI

Closes #53500

• GitHub Issue: [Python][Parquet] Comparing metadata or schemas with None can crash Python #53500

[jorisvandenbossche]

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