Lighting Should Only hold Vec<Entity> instead of TypeId<Vec<Entity>>

[re0312]

Objective

• After Reuse VisibleEntities in check_light_mesh_visibilty #13894, I noticed the performance of many_lights dropped from 120+ to 60+. I reviewed the PR but couldn't identify any mistakes. After profiling, I discovered that Hashmap::Clone was very slow when its not empty, causing extract_light to increase from 3ms to 8ms.
• Lighting only checks visibility for 3D Meshes. We don't need to maintain a TypeIdMap for this, as it not only impacts performance negatively but also reduces ergonomics.

Solution

• use VisibleMeshEntities for lighint visibility checking.

Performance

cargo run --release --example many_lights --features bevy/trace_tracy
name="bevy_pbr::light::check_point_light_mesh_visibility"}

system{name="bevy_pbr::render::light::extract_lights"}

Migration Guide

now SpotLightBundle , CascadesVisibleEntities and CubemapVisibleEntities use VisibleMeshEntities instead of VisibleEntities

[mnmaita]

A few doc comments would be great to be able to differentiate this from VisibleEntities

[pcwalton]

Seems fine. Lights could in theory affect other types of objects, but that would require a lot of refactoring, so we can specialize them to Meshes for now.