Ava UI: Content Dialog Fixes (#6482)

* Don’t use ContentDialogHelper when not necessary

* Remove `ExtendClientAreaToDecorationsHint`

src/Ryujinx/UI/Windows/ContentDialogOverlayWindow.axaml.cs

@@ -9,7 +9,6 @@ namespace Ryujinx.Ava.UI.Windows
         {
             InitializeComponent();
 
-            ExtendClientAreaToDecorationsHint = true;
             TransparencyLevelHint = new[] { WindowTransparencyLevel.Transparent };
             WindowStartupLocation = WindowStartupLocation.Manual;
             SystemDecorations = SystemDecorations.None;

src/Ryujinx/UI/Windows/DownloadableContentManagerWindow.axaml.cs

@@ -47,7 +47,7 @@ namespace Ryujinx.Ava.UI.Windows
 
             contentDialog.Styles.Add(bottomBorder);
 
-            await ContentDialogHelper.ShowAsync(contentDialog);
+            await contentDialog.ShowAsync();
         }
 
         private void SaveAndClose(object sender, RoutedEventArgs routedEventArgs)

src/Ryujinx/UI/Windows/TitleUpdateWindow.axaml.cs

@@ -49,7 +49,7 @@ namespace Ryujinx.Ava.UI.Windows
 
             contentDialog.Styles.Add(bottomBorder);
 
-            await ContentDialogHelper.ShowAsync(contentDialog);
+            await contentDialog.ShowAsync();
         }
 
         private void Close(object sender, RoutedEventArgs e)