Ensure sensor tasks are included in _ensure_tasks() output after ShortCircuitOperator

[kyungjunleeme]

#53455
#52869

• Added two unit tests to verify that sensor tasks are properly included in the output of _ensure_tasks() when placed downstream of ShortCircuitOperator.
• One test uses a custom BaseSensorOperator-based sensor (SucceedingSensor) to simulate success.
• The second test verifies behavior with the built-in S3KeySensor, testing both deferrable and non-deferrable modes.
• Both tests assert that the sensor task is not skipped or filtered out by _ensure_tasks() and that it is an instance of SDKBaseOperator.

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[kyungjunleeme]

file location is can be moved (if everyone wants)

[kyungjunleeme]

I'm closing this PR because the test I wrote isn't in the most appropriate location. I think it would be better to add more diverse test cases within the existing test module where similar tests already exist.