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.Shared/GameObjects/Components/Pulling/SharedPullerComponent.cs

@@ -52,7 +52,7 @@ namespace Content.Shared.GameObjects.Components.Pulling
         {
             base.HandleMessage(message, component);
 
-            if (!(message is PullMessage pullMessage) ||
+            if (message is not PullMessage pullMessage ||
                 pullMessage.Puller.Owner != Owner)
             {
                 return;