airflowctl: fix datetime.datetime CLI parameters rejecting all input

[bramhanandlingala]

closes: #70232

What

datetime.datetime-typed CLI parameters in airflowctl (e.g.
dagrun list --start-date/--end-date) rejected every input value.

Root cause

_python_type_from_string() in cli_config.py mapped
datetime.datetime to the bare class as the argparse type=
callable. argparse calls type(value) on the raw CLI string, so it
tried datetime.datetime("2026-07-01") — but that constructor expects
positional (year, month, day, ...) ints, not a string, so it always
raised TypeError, regardless of the input format.

Fix

Added iso_datetime_type(), a real parser using
datetime.datetime.fromisoformat(), and mapped datetime.datetime to
it instead of the bare class. This mirrors the existing fix already
applied for dict → json_dict_type.

[bramhanandlingala]

@ bugraoz93, @dheerajturaga, @henry3260 and @potiuk @kaxil
request you please review and approve for merge this fix

[bramhanandlingala]

@ bugraoz93, @dheerajturaga, @henry3260 and @potiuk @kaxil @Lee-W @shahar1

Did I miss anyone in the list, please advise
after a while this code fix would be stale , trying to get approval as soon as possible, any approvals or guidance is motivation to improve my work, please help

[henry3260]

Thanks for the fix!

[henry3260]

Suggested change

	"""An ISO-8601 datetime string (date-only or full) is parsed into a datetime.
	Regression test for https://github.com/apache/airflow/issues/70232: previously the
	bare ``datetime.datetime`` class was used as the argparse ``type=`` callable, so
	argparse called ``datetime.datetime(value)`` on the raw string, which always raised
	a ``TypeError`` regardless of the input.
	"""
	"""An ISO-8601 datetime string (date-only or full) is parsed into a datetime."""

[henry3260]

Could we add a test like this?

def test_command_factory_wires_iso_parser_to_datetime_params(self):
    """A generated datetime CLI arg parses an ISO date end to end."""
    command_factory = CommandFactory()
    dagrun_list_args = []
    for group in command_factory.group_commands:
        if group.name != "dagrun":
            continue
        for sub in group.subcommands:
            if sub.name == "list":
                dagrun_list_args = list(sub.args)
                break
    start_date_arg = next(a for a in dagrun_list_args if a.flags == ("--start-date",))
    assert start_date_arg.kwargs["type"]("2026-07-01") == datetime.datetime(2026, 7, 1)

[shahar1]

See #70437 (review)