[effects/presentwindows] Use windowFrameGeometryChanged

Summary:
Use windowFrameGeometryChanged rather than windowGeometryShapeChanged
because we are interested only in frame geometry changes.

Reviewers: #kwin, davidedmundson

Reviewed By: #kwin, davidedmundson

Subscribers: kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D26907