Remove unnecessary dependency on KPimGAPI
Summary:
Couldn't find any traces of it anymore, after the removal in
572b6d6808b1153b2de6b701e6f9c3ee852b99b5.
Test Plan: cmake .. && make
Reviewers: KDE PIM
Tags: KDE PIM
Differential Revision: https://phabricator.kde.org/D4670