manually quit kauth's mainloop
kauth helpers have a qcoreapplication started which auto-terminates after
10 seconds of idle time. this would be an added time out on top of our
life time management that is not necessary. to prevent this additional
delay simply quit the qapplication directly.
this makes helper termination almost instantaneous even when the dbus
client disappears due to crash or SIGINT, and largely removes the
need to call stopHelper altogether.
both partitionmanager and calamares instantly quit the helper no matter how the client process gets terminated
other than that everything seems to work as before
Differential Revision: https://phabricator.kde.org/D21559