Release Testing: Verify FLINK-34037 Improve Serialization Configuration and Usage in Flink

This issue aims to verify FLIP-398.

Volunteers can verify it by following the doc changes. Basically, two parts need to be verfied:

1. The old way of configuring serialization via hard-code method calls still works:
   • ExecutionConfig#registerType (for both POJO and generic types)
   • ExecutionConfig#addDefaultKryoSerializer
   • ExecutionConfig#registerTypeWithKryoSerializer
2. The new way of configuring serialization via config option pipeline.serialization-config also works for:
   • Regieter serializer for POJO types
   • Register Kryo serializer for generic types
   • Register Kryo serializer as the default Kryo serializer for types
   • Register custom type info factories