Let ArrowArrayStreamReader handle schema with attached metadata + do schema checking

[jonded94]

Which issue does this PR close? / Rationale for this change

Solves an issue discovered during #8790, namely that ArrowArrayStreamReader does not correctly expose schema-level metadata and does not check whether the StructArray constructed from the FFI stream actually in general corresponds to the expected schema.

What changes are included in this PR?

• Change how RecordBatch is construted inside ArrowArrayStreamReader such that it holds metadata and schema validity checks are done.
• Augment FFI tests with schema- and column-level metadata.

Are these changes tested?

Yes, both _test_round_trip_export and _test_round_trip_import now test for metadata on schema- and column-level.

Are there any user-facing changes?

Yes, ArrowArrayStreamReader now is able to export RecordBatch with schema-level metadata, and the interface has increased security since it actually checks for schema validity.