Enable mapped task argument overrides in airflow tasks test

[kevinhongzl]

Summary

Task parameters were immutable when debugging dynamic task mappings using the CLI airflow tasks test. This meant we couldn't override parameters on the fly, nor could we easily test mapped tasks that relied on upstream XCom arguments. This PR updates the Airflow CLI to support local testing of dynamically mapped tasks.

closes: #56953

Params Overrides Behavior

The tables below outline how our updated airflow tasks test handles combinations of expansion types, argument sources, and the presence of CLI task parameter overrides.

1. Positional Arguments from expand()

Argument Type	With CLI Task Params	Without CLI Task Params
Literal Values	Overrides the original task parameters with the single provided parameter value.	Runs tests using the original values defined for that specific map index in the DAG.
XCom Arguments	Uses the user-provided input value to successfully execute and test the task.	Fails immediately with the expected XCom not found exception.

2. Keyword Arguments from expand_kwargs()

Argument Type	With CLI Task Params	Without CLI Task Params
Literal Values	Updates the mapped keyword arguments for that index with the new CLI task parameters.	Runs tests using the baseline keyword arguments defined for that map index in the DAG.
XCom Arguments	Uses the user-provided input dictionary to successfully execute and test the task.	Fails immediately with the expected XCom not found exception.

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