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.Shared/Light/SharedHandheldLightSystem.cs

@@ -80,7 +80,7 @@ public abstract class SharedHandheldLightSystem : EntitySystem
         if (component.ToggleActionEntity != null)
             _actionSystem.SetToggled(component.ToggleActionEntity, component.Activated);
 
-        _appearance.SetData(uid, ToggleableLightVisuals.Enabled, component.Activated, appearance);
+        _appearance.SetData(uid, ToggleableVisuals.Enabled, component.Activated, appearance);
     }
 
     private void AddToggleLightVerb(Entity<HandheldLightComponent> ent, ref GetVerbsEvent<ActivationVerb> args)