applets/kicker: Remove unused commands from Messages.sh

Summary: "find . -name \*.rc -o -name \*.ui -o -name \*.kcfg" returns 0 files.

Test Plan: Run extract-messages.sh, compare the resulting .pot file.

Reviewers: ltoscano, bshah, davidedmundson

Reviewed By: davidedmundson

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D24063