Don't unintentionally change font rendering when rendering preview images
Summary:
Font rendering settings are changed temporarily to render preview images. The changed settings were
reverted, but never reapplied. This way rendering preview images could alter the user's font rendering
configuration.
Reviewers: ngraham
Reviewed By: ngraham
Subscribers: ngraham, plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D14480