Return focus from controller applet after completion (#2218)

* Return focus from controller applet after completion

This fixes controller applet related in Mario Kart 8 Deluxe, in 2 player mode or when opening the applet in character select.

* Return focus for player select

Ryujinx.HLE/HOS/Applets/PlayerSelect/PlayerSelectApplet.cs

@@ -30,6 +30,8 @@ namespace Ryujinx.HLE.HOS.Applets
 
             AppletStateChanged?.Invoke(this, null);
 
+            _system.ReturnFocus();
+
             return ResultCode.Success;
         }