Support device type for KeyEvent

[JSUYA]

        KeyboardListener(
              autofocus: true,
              focusNode: FocusNode(),
              onKeyEvent: (event) {
                print(event.deviceType.label);
                print(event);
              },
              child: ...
            ),

I tested with above code, but remote controller still returns keyboard. When I checking with log from the engine's FlutterEngineSendKeyEvent(), passed device_type is does not seem to be the problem. This needs to be investigated some more.