Load QtQuickSettings for software rendering
We had support for falling back on errors yet somehow
the initial basic loading was missing.
Summary: BUG: 347772
Test Plan: Compiles
Reviewers: Plasma, broulik
Reviewed By: Plasma, broulik
Subscribers: plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D14708