Fix bytea TEXT encoding for PostgreSQL data rows

[jonasHanhan]

Summary

• Encode bytea values as PostgreSQL TEXT format (\x + hex) to avoid truncation in clients
• Keep binary format behavior unchanged
• Update unit test to assert TEXT bytea encoding

Related issues

• Fixes When using ShardingSphere Proxy 5.5.2 with a PostgreSQL database, reading bytea fields results in the loss of trailing bytes, and the number of bytes lost varies across different data entries. #37238

Testing

• ./mvnw -pl database/protocol/dialect/postgresql -am -DskipITs -Dspotless.skip=true -Dtest=PostgreSQLDataRowPacketTest -Dsurefire.failIfNoSpecifiedTests=false test