Fix a bunch of compiler warnings (#10518)

Content.Client/Kitchen/UI/MicrowaveBoundUserInterface.cs

@@ -18,7 +18,6 @@ namespace Content.Client.Kitchen.UI
     public sealed class MicrowaveBoundUserInterface : BoundUserInterface
     {
         [Dependency] private readonly IEntityManager _entityManager = default!;
-        [Dependency] private readonly IPrototypeManager _prototypeManager = default!;
 
         private MicrowaveMenu? _menu;
 

Content.Client/Kitchen/Visualizers/MicrowaveVisualizer.cs

@@ -13,6 +13,7 @@ namespace Content.Client.Kitchen.Visualizers
     [UsedImplicitly]
     public sealed class MicrowaveVisualizer : AppearanceVisualizer
     {
+        [Obsolete("Subscribe to AppearanceChangeEvent instead.")]
         public override void OnChangeData(AppearanceComponent component)
         {
             base.OnChangeData(component);

Content.Client/Kitchen/Visualizers/ReagentGrinderVisualizer.cs

@@ -7,6 +7,7 @@ namespace Content.Client.Kitchen.Visualizers
 {
     public sealed class ReagentGrinderVisualizer : AppearanceVisualizer
     {
+        [Obsolete("Subscribe to AppearanceChangeEvent instead.")]
         public override void OnChangeData(AppearanceComponent component)
         {
             base.OnChangeData(component);