Implement execution_timeout semantics for AirbyteTriggerSyncOperator in deferrable mode

[SameerMesiah97]

Description

This change enforces execution_timeout for AirbyteTriggerSyncOperator in deferrable mode.

Previously, when the operator deferred, execution_timeout was not enforced, allowing Airbyte jobs to continue running after the Airflow task had timed out.

The operator now computes an execution deadline before deferring, the trigger emits a timeout event when the deadline is exceeded, and the operator cancels the Airbyte job and fails the task when the event is received.

Rationale

In non-deferrable mode, execution_timeout is enforced by the scheduler, which terminates the task process and invokes on_kill() to cancel the external Airbyte job.

In deferrable mode, execution is handed off to a trigger running in the triggerer process, so there is no worker process to terminate. However, this does not change the expected task semantics. From a user perspective, execution_timeout is a hard task-level limit and should behave consistently regardless of execution mode.

Without explicit handling in the trigger/operator interaction, execution_timeout becomes a no-op in deferrable mode, leading to leaked Airbyte jobs and inconsistent behavior.

This is the same class of issue addressed in PR #61472 for DbtCloudRunJobOperator.

Notes

• The existing timeout parameter only controls how long the operator waits for job completion and does not imply cancellation.
• When both execution_timeout and timeout are set, the earlier deadline takes precedence.
• Job cancellation on timeout is best-effort. Failures during cancellation are logged and do not mask the original timeout failure.
• In execute_complete, generic AirflowException raises have been replaced with more appropriate, specific exception types.
• Before/after behavior screenshots can be provided upon request.

Tests

• Added a trigger-level test asserting a timeout event when the execution deadline is exceeded.
• Added an operator-level test verifying job cancellation on execution timeout.
• Added an operator-level test verifying error propagation when job cancellation fails.
• Modified a trigger serialization test to ensure the optional execution_deadline field is always serialized.

Documentation

• Updated the trigger docstring to document the new execution_deadline parameter.
• Updated the operator docstring to clarify the behavior of timeout vs execution_timeout; added an entry for execution_timeout.

Backwards Compatibility

This change does not modify public APIs or method signatures.

Behavior is changed such that Airbyte jobs are now cancelled when execution_timeout is reached in deferrable mode. Previously, jobs could continue running after the task timed out.

Closes: #64048