[FLINK-37820][table-planner] Support AsyncScalarFunction 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 AsyncScalarFunction and is not loaded already, the plan will fail to load, cause RexNodeJsonDeserializer does not know about the ASYNC_SCALAR function kind. This should be supported, cause in this regard, SCALAR and ASYNC_SCALAR has no relevant difference.

Brief change log

• Add ASYNC_SCALAR 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:

• 2764998 Azure: SUCCESS

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