Fix wireguard to detect launchd on Monterey

[palmerc]

I have noticed that wireguard no longer starts on Monterey as a launchd service. Investigation suggests that the check for 'domain' in the output of launchctl procinfo $$ no longer works. I have switched the logic to check for the '(pid XX is not managed by launchd)' message instead which works on Big Sur and Monterey in my testing.