Remove SessionController from the factory during deletion

Authored by mglb on Nov 26 2019, 1:05 AM.

Description

Remove SessionController from the factory during deletion

Fixes warning:

"kf5.kxmlgui: 0xXXXXXXXXXXXX deleted without having been removed from
the factory first. This will leak standalone popupmenus and could lead
to crashes."