[FLINK-37599][table] Support column expansion for PTF on_time columns

[twalthr]

What is the purpose of the change

This commit extends column expansion support to Process Table Functions (PTF) with on_time columns, generalizing the existing logic that previously only worked for window table functions.

Brief change log

• Generalized column expansion logic - Extended the mechanism from window TVFs (TUMBLE, SESSION, etc.) to all PTFs that have an on_time argument
  • Improved argument extraction - Added extractOperandByArgName() to handle both positional and named arguments when extracting the on_time descriptor
  • Renamed concepts - Changed declaredDescriptorColumn to isDeclaredOnTimeColumn and related names to better reflect their purpose
  • Enhanced test coverage - Added tests for PTF column expansion with both single and multi-input table arguments

Verifying this change

This change added tests and can be verified as follows:

ColumnExpansionTest.java - Added PTF test cases

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? JavaDocs

[flinkbot]

CI report:

• 15edf06 Azure: SUCCESS

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