[Parquet] Reduce size of ParquetMetadata when encryption feature is enabled #8469

Is your feature request related to a problem or challenge? Please describe what you are trying to do.

One thing I noticed while reviewing #8445 (review) with @etseidl was that the ParquetMetaData structure is substantially larger in memory when encryption is enabled.

Something else I noticed while working on #8340 is that the
file decryption properties are clone (dee-copied) around a lot.

Describe the solution you'd like

This is unnecessary and could be avoided by using Arc<FileDecryptionProperties> instead of FileDecryptionProperties directly.

Describe alternatives you've considered

Additional context