fix: Handle input_file_name() pushdown into ParquetSource with filter pushdown enabled

[AdamGS]

Which issue does this PR close?

• Closes input_file_name() in a WHERE clause errors when parquet pushdown_filters is enabled #23531.

Rationale for this change

input_file_name() is FileSource dependent like file_row_index(), and therefore shouldn't be pushed down into a filter.

What changes are included in this PR?

PushdownChecker now handles both UDFs consistently.

If we keep adding this sort of metadata functions, we might want a better API to detect them, but for now I think this is a reasonable approach that isn't very invasive.

Are these changes tested?

Additional SLT test that verifies that both function behave correctly with pushdown either enabled or disabled.

Are there any user-facing changes?

None

[codecov-commenter]

Codecov Report

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Additional details and impacted files

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[AdamGS]

I think this is a reasonable fix especially with the target date for the release getting closer.
I'm experimenting with something more powerful - while we can't push it down, maybe we can treat it similarly to table partitions/literal columns, so a predicate like input_file_name() LIKE '%first.parquet' can be used by the FilePruner.