Fix: ensure bool(LazySelectSequence) returns True or False

[johncmerfeld]

closes: #43977

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It is possible for bool(LazySelectSequence) to return None. This can break Xcom Jinja templates that retrieve null values from the airflow database

[boring-cyborg]

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[potiuk]

Could you please add a unit test covering this case?

[johncmerfeld]

Could you please add a unit test covering this case?

I'd love to; I'm just a little unsure where it would go. I couldn't find any module that tests the behavior of LazySelectSequence directly. I'd appreciate any advice you have on this!