global menu,rename menuHidden to visible
Summary:
--as @mart requested we can rename "menuHidden" property
to "visible" in order to follow Qt naming
Test Plan:
--check that global menu applet is functioning the same
way as when using removed menuHidden property
Reviewers: Plasma, mart, davidedmundson
Reviewed By: Plasma, mart
Subscribers: mart, plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D17107