Update usages of ! is with is not (#2584)

* Update usages of ! is with is not

* Content.IntegrationTests commit

* Content.Server commit

* Content.Shared commit

Co-authored-by: Metal Gear Sloth <metalgearsloth@gmail.com>

Content.Client/GameObjects/Components/Disposal/DisposalRouterBoundUserInterface.cs

@@ -42,7 +42,7 @@ namespace Content.Client.GameObjects.Components.Disposal
         {
             base.UpdateState(state);
 
-            if (!(state is DisposalRouterUserInterfaceState cast))
+            if (state is not DisposalRouterUserInterfaceState cast)
             {
                 return;
             }