Fix debug collision shape reduced opacity when instanced

[aryan-11825114]

Fixes #102806

Before	After

[akien-mga]

Based on the code this was intentional in #90644, so CC @BattyBovine @Calinou to re-assess.

[Calinou]

This is indeed intentional behavior, so that the collision gizmos look less intrusive in complex 3D scenes.

However, we could choose to disable the reduction in gizmo opacity of instanced subscenes if #98370 is implemented.

[aryan-11825114]

This is indeed intentional behavior, so that the collision gizmos look less intrusive in complex 3D scenes.

However, we could choose to disable the reduction in gizmo opacity of instanced subscenes if #98370 is implemented.

I agree, perhaps this could be merged after #98370 has been merged

[HerrSersch]

This is indeed intentional behavior, so that the collision gizmos look less intrusive in complex 3D scenes.

That makes sense. After reading everything, I think my issue might be a case of "I misunderstood and misused the feature and then wondered why it doesn't work as intended".

I thought this was a bug because I was creating reusable trigger scenes with an Area3D as the root and a CollisionShape3D as a child and noticed they were much more transparent when I used them in a level than when I was editing them. However, I now think this is an user error for the following reason:

Because the CollisionShape3D is a child node, I can't adjust its size directly in the map where I'm using the trigger. So I scaled the entire instanced trigger scene instead. The editor complains right away about the non-uniformly scaled Area3D, which I ignored, because I couldn't find any problems while testing. But technically, it's still the wrong approach.

The correct approach would either be to activate "Editable Children" for the instanced trigger and resize the CollisionShape3D manually or to not include the collider in the scene and add it manually in the level. In both cases, the color would be at the intended intensity.