Give each task its own start trigger arguments in standard sensors

[potiuk]

start_trigger_args is a class attribute on DateTimeSensorAsync, TimeSensor and
FileSensor, and each one assigned through it in __init__:

self.start_trigger_args.trigger_kwargs = dict(moment=self._moment, ...)

That mutates the shared class-level object instead of creating an instance attribute, so
every task built from the operator ends up advertising the arguments of whichever task was
constructed last.

Reproducer on main:

a = DateTimeSensorAsync(task_id="a", target_time=datetime(2030, 1, 1), start_from_trigger=True)
b = DateTimeSensorAsync(task_id="b", target_time=datetime(2040, 6, 6), start_from_trigger=True)

a.start_trigger_args is b.start_trigger_args        # True
a.start_trigger_args.trigger_kwargs["moment"]       # 2040-06-06  <- b's moment

With start_from_trigger=True the task starts directly in the triggerer from these
arguments, so two DateTimeSensorAsync tasks in one Dag both wait for the same moment. The
same applies to TimeSensor's moment and to FileSensor's filepath, recursive,
poke_interval and timeout.

Each sensor now replaces start_trigger_args with a fresh copy via dataclasses.replace,
which binds an instance attribute and leaves the class-level template untouched for the next
task built from it.

Regression tests are added for all three sensors; each fails on main.

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Was generative AI tooling used to co-author this PR?

• Yes — Claude Code (Opus 5)

Generated-by: Claude Code (Opus 5) following the guidelines

[github-actions]

Backport failed to create: v3-3-test. View the failure log Run details

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Status	Branch	Result
❌	v3-3-test

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cherry_picker 16b4e62 v3-3-test

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the files that need manual conflict resolution.

After you have resolved the conflicts, you can continue the backport process by running:

cherry_picker --continue

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