Enable nullability in Content.Client (#3257)

* Enable nullability in Content.Client

* Remove #nullable enable

* Merge fixes

* Remove Debug.Assert

* Merge fixes

* Fix build

* Fix build

Content.Client/GameObjects/Components/Power/AME/AMEControllerBoundUserInterface.cs

@@ -9,11 +9,10 @@ namespace Content.Client.GameObjects.Components.Power.AME
     [UsedImplicitly]
     public class AMEControllerBoundUserInterface : BoundUserInterface
     {
-        private AMEWindow _window;
+        private AMEWindow? _window;
 
         public AMEControllerBoundUserInterface(ClientUserInterfaceComponent owner, object uiKey) : base(owner, uiKey)
         {
-
         }
 
         protected override void Open()
@@ -31,7 +30,6 @@ namespace Content.Client.GameObjects.Components.Power.AME
             _window.RefreshPartsButton.OnPressed += _ => ButtonPressed(UiButton.RefreshParts);
         }
 
-
         /// <summary>
         /// Update the ui each time new state data is sent from the server.
         /// </summary>
@@ -58,7 +56,7 @@ namespace Content.Client.GameObjects.Components.Power.AME
 
             if (disposing)
             {
-                _window.Dispose();
+                _window?.Dispose();
             }
         }
     }