plugins/openvscode-drive: Work around race condition when launching noVNC proxy server

If the noVNC proxy comes up after the VSCode server, our proxy will not find the former's URL in the
stdout log.  Sacrifice two seconds of loading time to avoid this problem.

Author: solb

plugins/openvscode-drive

@@ -34,6 +34,7 @@ then
 
 	Xvnc -SecurityTypes None -localhost -nolisten local ":$display" 2>/dev/null &
 	novnc_proxy --vnc ":$((X11_PORT + display))" --listen $((VNC_PORT + display)) 2>/dev/null &
+	sleep 2
 
 	export DISPLAY=":$display"
 fi