Fix window positions not saving (#35055)

Co-authored-by: Kevin Zheng <kevinz5000@gmail.com>

Content.Client/Atmos/UI/GasAnalyzerBoundUserInterface.cs

@@ -1,4 +1,5 @@
 using Robust.Client.GameObjects;
+using Robust.Client.UserInterface;
 using static Content.Shared.Atmos.Components.GasAnalyzerComponent;
 
 namespace Content.Client.Atmos.UI
@@ -16,9 +17,7 @@ namespace Content.Client.Atmos.UI
         {
             base.Open();
 
-            _window = new GasAnalyzerWindow();
-            _window.OnClose += OnClose;
-            _window.OpenCenteredLeft();
+            _window = this.CreateWindowCenteredLeft<GasAnalyzerWindow>();
         }
 
         protected override void ReceiveMessage(BoundUserInterfaceMessage message)