Support Ref types in Avro Reader. #18811
Description
Is your feature request related to a problem or challenge?
Currently Ref types are not supported at all, if the reader is set to infer the schema from the file, we'll enter an unreachable block, if we manually provide an Arrow schema, and the writer_schema has a Ref somewhere - it's worse, any Ref type will just appear as Null in the data without any explanation.
Describe the solution you'd like
Refs should be supported, as far as arrow can support them.
Describe alternatives you've considered
No response
Additional context
No response