[FLINK-38957][table-planner] Support ProcessTableFunction registration via CompiledPlan

[ferenc-csaky]

What is the purpose of the change

Currently, if you try to load a CompiledPlan that contains any UDF that extends ProcessTableFunction and is not loaded already, the plan will fail to load, cause RexNodeJsonDeserializer does not know about the PROCESS_TABLE function kind.

Brief change log

• Add PROCESS_TABLE function kind to RexNodeJsonDeserializer.
• Provide unit tests to cover the added logic.

Verifying this change

Extended RexNodeJsonSerdeTest unit tests that covers the added logic.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): no
• The public API, i.e., is any changed class annotated with @Public(Evolving): no
• The serializers: no
• The runtime per-record code paths (performance sensitive): no
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: no
• The S3 file system connector: no

Documentation

• Does this pull request introduce a new feature? no
• If yes, how is the feature documented? not applicable

[flinkbot]

CI report:

• f2e4098 Azure: SUCCESS

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[davidradl]

The code seems good. I am curious about the name of this class. It is possible to have a non serializable PTF? If not, I suggest naming this something like MyProcessTableFunction to prevent confusion. If we can reasonably have a non serializable PTF, we should have a test for this.