Handle TriggerTargets that are combinations for components/entities

[BenjaminBrienen]

Objective

Fixes #14074

It is currently not possible to issues a trigger that targets a specific list of components AND a specific list of entities

Solution

We can now use ((A, B), (entity_1, entity_2)) as a trigger target, as well as the reverse

Testing

Added a unit test.

The triggering rules for observers are quite confusing:

Triggers once per entity target

For each entity target, an observer system triggers if any of its components matches the trigger target components (but it triggers at most once, since we use an internal counter to make sure that an observer can run at most once per entity target)

(copied from #14563)

[BenjaminBrienen]

I feel like I leveled up my macro skills on this one.