config/output: reconfigure input devices after full output init
config/output: reconfigure input devices after full output init

Previously in 3de1a39, it "worked by accident" in my testing since the
display being used in `map_to_output` was initialized first (the map
would not be applied because the display hadn't actually come online
yet), and was followed by a second display (at which point the map would
get applied for the first display).

Refs #5231

1ace/sway,1ace/sway,1ace/sway