[libinput] Try to dispatch events directly after setup

Without we might end in a race as kwin_wayland might start the Xwayland
server before we have a populated seat interface.

libinput/connection.cpp

@@ -97,6 +97,7 @@ void Connection::setup()
             active ? m_input->resume() : m_input->suspend();
         }
     );
+    handleEvent();
 }
 
 void Connection::handleEvent()