Disable keyboard controller input while swkbd is open (foreground) (second attempt) (#6808)

* Block input updates while swkbd is open in foreground mode

* Flush internal driver state before unblocking input updates

* Rename Flush to Clear and remove unnecessary attribute

* Clear the driver state only if the GamepadDriver isn't null

src/Ryujinx/Input/AvaloniaKeyboard.cs

@@ -195,7 +195,7 @@ namespace Ryujinx.Ava.Input
 
         public void Clear()
         {
-            _driver?.ResetKeys();
+            _driver?.Clear();
         }
 
         public void Dispose() { }