remote reboot with support proxy should reconnect

[tridge]

When supporting users with the ArduPilot support proxy at https://support.ardupilot.org it is really annoying each time I need to reboot a board (eg. when changing an enable parameter, clearing an error etc). If the user uses the "preflight reboot" option in MissionPlanner then it auto reconnects on USB. If I sent a remote reboot command from the support GCS then it doesn't, so I constantly need to ask the user to run a preflight reboot, which also means they have to stay by the MissionPlanner GCS and wait for me to ask for a reboot
It would be great if a remote reboot behaved like a "preflight" reboot