Improve trigger assign_unassigned method

[hussein-awala]

Improve trigger assign_unassigned method by merging alive_triggerer_ids and get_sorted_triggers queries to reduce latency and memory usage.

[uranusjr]

Do we even need to do this outside of get_sorted_triggers in the first place? I wonder why we can’t just pass health_check_threshold into the function and do the subquery there instead…

[hussein-awala]

Yes, we can do that, but I think keeping it like this will keep the unit tests simple, as we can pass the IDs in a list instead of setting up the trigger table.

[uranusjr]

Maybe let’s add some annotation or docstring on get_sorted_triggers so future people know what to expect? At least they need to know to expect a subquery, not always a Python list or some iterable.