Do not use AUTOUIC, but ki18n_wrap_ui, as needed to integrate with ki18n

Summary:
Currently makes no difference as there are no translated strings yet
in the only UI file existing so far.
But can be a trap in the future, so prevent falling into that.

Reviewers: mreeves

Reviewed By: mreeves

Differential Revision: https://phabricator.kde.org/D27825