Remove some BUI boilerplate (#28399)

* Remove some BUI boilerplate

- The disposals overrides got removed due to the helper method handling it.
- Replace window creation with CreateWindow helper.
- Fixed some stinky code which would cause exceptions.

* More

* moar

* weh

* done

* More BUIs

* More updates

* weh

* moar

* look who it is

* weh

* merge

* weh

* fixes

Content.Client/Fax/UI/FaxBoundUi.cs

@@ -25,10 +25,7 @@ public sealed class FaxBoundUi : BoundUserInterface
     {
         base.Open();
 
-        _window = new FaxWindow();
-        _window.OpenCentered();
-
-        _window.OnClose += Close;
+        _window = this.CreateWindow<FaxWindow>();
         _window.FileButtonPressed += OnFileButtonPressed;
         _window.CopyButtonPressed += OnCopyButtonPressed;
         _window.SendButtonPressed += OnSendButtonPressed;
@@ -104,11 +101,4 @@ public sealed class FaxBoundUi : BoundUserInterface
 
         _window.UpdateState(cast);
     }
-
-    protected override void Dispose(bool disposing)
-    {
-        base.Dispose(disposing);
-        if (disposing)
-            _window?.Dispose();
-    }
 }