Decouple Lights from Toggleable Visuals (and headphone music notes bugfix) (#35341)

* - Combine enum keys `ToggleableLightVisuals` and `ToggleVisuals` into `ToggleableVisuals`
- Rename `ToggleableLightVisualsComponent` to `ToggleableVisualsComponent` and `ToggleableLightVisualsSystem` to `ToggleableVisualsSystem`
  - (The `SpriteLayer` field on the component is now required because the old default of `light` doesn't make sense anymore)
- Make it so that `ToggleableVisualsComponent` works even when there's not a light attached to the entity
  - (Amazingly this seems to have only applied to  Headphones, but I can only imagine there are many other things people would like to do with simple toggleable visuals)
- Explicitly make `ItemTogglePointLightComponent`'s purpose to make `ToggleVisualsComponent` apply to `PointLightComponent`s on the same entity.
  - Add field `ToggleableVisualsColorModulatesLights`, which makes the `Color` appearance value of `ToggleableVisuals` modulate the color of lights on the same entity
  - Lots of prototype updates to uptake the above

* fix bad merge

* unbork robust

* blindly letting rider reformat stuff

* I guess I never cleaned up these imports at all

Content.Server/Atmos/EntitySystems/FlammableSystem.cs

@@ -282,7 +282,7 @@ namespace Content.Server.Atmos.EntitySystems
             // This is intended so that matches & candles can re-use code for un-shaded layers on in-hand sprites.
             // However, this could cause conflicts if something is ACTUALLY both a toggleable light and flammable.
             // if that ever happens, then fire visuals will need to implement their own in-hand sprite management.
-            _appearance.SetData(uid, ToggleableLightVisuals.Enabled, flammable.OnFire, appearance);
+            _appearance.SetData(uid, ToggleableVisuals.Enabled, flammable.OnFire, appearance);
         }
 
         public void AdjustFireStacks(EntityUid uid, float relativeFireStacks, FlammableComponent? flammable = null, bool ignite = false)