Wait for async task to complete (#7122)

This way exceptions thrown during the execution of CheckLaunchState()
will correctly invoke the unhandled exception handler
and cause Ryujinx to crash.

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

@@ -482,9 +482,7 @@ namespace Ryujinx.Ava.UI.Windows
                 LoadApplications();
             }
 
-#pragma warning disable CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
-            CheckLaunchState();
-#pragma warning restore CS4014 // Because this call is not awaited, execution of the current method continues before the call is completed
+            CheckLaunchState().Wait();
         }
 
         private void SetMainContent(Control content = null)