Stop unnecessarily killing IBus when applying keyboard layouts config

Summary: More details here: https://bugs.kde.org/show_bug.cgi?id=379930

Reviewers: xapienz, xuetianweng

Reviewed By: xapienz, xuetianweng

Subscribers: hein, xapienz, plasma-devel, Plasma

Tags: Plasma

Differential Revision: https://phabricator.kde.org/D6956