Enforce execution_timeout in deferrable DataprocSubmitJobOperator

[anor4k]

Why

DataprocSubmitJobOperator(deferrable=True) does not enforce execution_timeout. Once the operator defers, the synchronous execute() returns, and nothing bounds the deferral: self.defer() is called without a timeout, so the trigger polls the job forever. Even when a user passes defer(timeout=...) through a subclass, a framework-level trigger timeout resumes the task only to fail it — the Dataproc job itself keeps running, because the triggerer does not run the trigger's on_kill for a timeout resume.

In non-deferrable mode, exceeding execution_timeout raises AirflowTaskTimeout and on_kill() cancels the job. Deferrable mode silently loses both behaviors. The framework gap is acknowledged by # TODO: handle timeout in case of deferral in task-sdk/src/airflow/sdk/execution_time/task_runner.py.

This is the same class of issue already fixed for DbtCloudRunJobOperator (#61467 → #66449), AirbyteTriggerSyncOperator (#64048 → #64051), and KubernetesPodOperator (#67227 → #67229).

What

Mirrors the approach merged in #67229:

• Operator (dataproc.py): when execution_timeout is set, derive an absolute deadline anchored on ti.start_date (stable across re-deferrals) and pass it to DataprocSubmitTrigger as execution_deadline. Also pass timeout= to self.defer() as a framework backstop, with one polling interval of slack so the trigger's own deadline handling (which cancels the job) fires first.
• Trigger (triggers/dataproc.py): DataprocSubmitTrigger accepts an optional execution_deadline (epoch seconds). When the deadline passes while the job is still running, the trigger cancels the Dataproc job (unless cancel_on_kill=False) and emits a TIMED_OUT event.
• execute_complete: raises AirflowException on the TIMED_OUT event, failing the task.

generated/known_airflow_exceptions.txt is bumped for the one new raise AirflowException (only the dataproc line; the file has unrelated drift on main that a full --generate would also pick up).

Behavior is unchanged when execution_timeout is not set (execution_deadline=None, no defer timeout).

DataprocSubmitJobDirectTrigger (start-from-trigger path) has the same gap and could be handled in a follow-up.

Tests

• Trigger: deadline expiry cancels the job and yields TIMED_OUT; cancel_on_kill=False skips the cancel; serialization includes execution_deadline.
• Operator: deferral carries the computed deadline and a defer timeout; execute_complete raises on TIMED_OUT.

providers/google/tests/unit/google/cloud/triggers/test_dataproc.py -k TestDataprocSubmitTrigger: 7 passed, 2 skipped
providers/google/tests/unit/google/cloud/operators/test_dataproc.py -k TestDataprocSubmitJobOperator: 22 passed

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