Bug#1016785: Can't change user password on a "System Settings" (polkit dialog doesn't appear)

[Rik Mills]

Reported upstream in: https://bugs.kde.org/show_bug.cgi?id=459309
Fixed by: 
https://invent.kde.org/plasma/plasma-workspace/-/commit/84dcfc45b9a354827b9bbf6ae58902d04e8fe915