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.Client/Toggleable/ToggleableVisualsComponent.cs

@@ -0,0 +1,30 @@
+using Content.Shared.Hands.Components;
+
+namespace Content.Client.Toggleable;
+
+/// <summary>
+/// Component that handles toggling the visuals of an entity, including layers on an entity's sprite,
+/// the in-hand visuals, and the clothing/equipment visuals.
+/// </summary>
+/// <see cref="ToggleableVisualsSystem"/>
+[RegisterComponent]
+public sealed partial class ToggleableVisualsComponent : Component
+{
+    /// <summary>
+    /// Sprite layer that will have its visibility toggled when this item is toggled.
+    /// </summary>
+    [DataField(required: true)]
+    public string? SpriteLayer;
+
+    /// <summary>
+    /// Layers to add to the sprite of the player that is holding this entity (while the component is toggled on).
+    /// </summary>
+    [DataField]
+    public Dictionary<HandLocation, List<PrototypeLayerData>> InhandVisuals = new();
+
+    /// <summary>
+    /// Layers to add to the sprite of the player that is wearing this entity (while the component is toggled on).
+    /// </summary>
+    [DataField]
+    public Dictionary<string, List<PrototypeLayerData>> ClothingVisuals = new();
+}