Load localization catalog for slideshow config window
Summary: It was reported by Victor Ryzhykh that this patch fixes localization of the wallpaper slideshow config window.
Test Plan:
- Open the config window in some ~100%-translated locale (ca, pt, sv, uk).
- All messages should be translated.
Reviewers: Plasma, Localization, ngraham
Reviewed By: ngraham
Subscribers: ngraham, plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D26584