[libkwineffects] Don't expose the fullscreen effect lock to the public API
Summary:
The fullscreen effect lock is purely an implementation detail of the
AnimationEffect, we don't need to have it in the public API.
Test Plan: KWin still compiles.
Reviewers: KWin, davidedmundson
Reviewed By: KWin, davidedmundson
Subscribers: kwin
Tags: KWin
Differential Revision: https://phabricator.kde.org/D16075