Kafka Connect: UUID columns fail to write with Parquet (ClassCastException) #17076

Apache Iceberg version
main @ 49b89a8

Query engine
Kafka Connect (N/A — not Spark/Flink)

Please describe the bug
RecordConverter.convertUUID() (kafka-connect/kafka-connect/src/main/java/org/apache/iceberg/connect/data/RecordConverter.java line 508) converts UUID values to byte[] when the target file format is Parquet. The Parquet UUID writer, ParquetValueWriters.uuids() (via BaseParquetWriter's default visitor), expects a java.util.UUID and converts to bytes internally, so a byte[] fails to cast during write. ORC (GenericOrcWriters.uuids()) and Avro both write UUID directly — only the Parquet branch in convertUUID diverges from this.

Steps to reproduce
Sink a record with a UUID field to an Iceberg table using the default file format (Parquet). IcebergWriter.convertToRow() calls convertUUID(), which returns byte[]; the Parquet writer stack then throws on write.
Expected: the record writes successfully.
Actual: ClassCastException: class [B cannot be cast to class java.util.UUID.

Additional context
The byte[] conversion matched the Parquet writer contract before PR #11904 ("Parquet: Add readers and writers for the internal object model", merged 2025-01-24) changed ParquetValueWriters' UUID writer to accept UUID directly. kafka-connect was never updated to follow, making this a regression from that writer-contract change.