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PARQUET-2411: [C++][Parquet] Allow reading dictionary without reading data via ByteArrayDictionaryRecordReader (#39153)


### Rationale for this change
This proposes an API to read only the dictionary  from ByteArrayDictionaryRecordReader, enabling possible uses cases where the caller just want to check the dictionary content.

### What changes are included in this PR?

New APIs to enable reading dictionary with RecordReader.

### Are these changes tested?
Unit tests.

### Are there any user-facing changes?

New APIs without breaking existing workflow.

Authored-by: jp0317 <zjpzlz@gmail.com>
Signed-off-by: mwish <maplewish117@gmail.com>