snapcraft: Add desktop plug (#6069)
snapcraft: Add desktop plug (#6069)

Without the desktop plug, launching the syncthing snap will not launch a browser window to the admin UI. Adding this one line will fix that. Tested here on my Ubuntu system with a build from tip of master.
wweich/syncthing,imsodin/syncthing,imsodin/syncthing,syncthing/syncthing,syncthing/syncthing,imsodin/syncthing,syncthing/syncthing,AudriusButkevicius/syncthing,syncthing/syncthing,wweich/syncthing,AudriusButkevicius/syncthing,wweich/syncthing,AudriusButkevicius/syncthing,AudriusButkevicius/syncthing,wweich/syncthing,syncthing/syncthing,imsodin/syncthing,imsodin/syncthing,syncthing/syncthing