Sort List by piece count does not work
Summary:
The sorting in the overview dialog did not work because the
QSortFilterProxyModel was not set up correctly
BUG: 376607
Test Plan:
Test if the sorting works by selecting the appropriate sorting
Reviewers: KDE Games, ltoscano
Reviewed By: ltoscano
Subscribers: ltoscano, KDE Games
Differential Revision: https://phabricator.kde.org/D7578