Fix world removal disabling all non-ecs functionality (#967)

Author: zeroZshadow

workers/unity/Packages/com.improbable.gdk.core/Utility/PlayerLoopUtils.cs

@@ -218,7 +218,7 @@ public static void RemoveFromPlayerLoop(World world)
                         return targetSystem.World != world;
                     }
 
-                    return false;
+                    return true;
                 }).ToArray();
             }