InputConfigDiag: Update GUI when config is reloaded

This makes the GUI show the settings that are loaded when the config
gets reloaded, instead of showing potentially outdated settings that
are not applied.

Source/Core/DolphinWX/InputConfigDiag.cpp

@@ -799,6 +799,8 @@ void GamepadPage::RefreshDevices(wxCommandEvent&)
   Pad::LoadConfig();
   HotkeyManagerEmu::LoadConfig();
 
+  UpdateGUI();
+
   Core::PauseAndLock(false, was_unpaused);
 }