Remove "Full Screen(All Monitors)" when only one monitor exists
Summary: When there is only one screen available the "Current Screen" and "Full Screen (All monitors)" options are identical, so this patch removes the latter.
Reviewers: Spectacle, ngraham
Reviewed By: Spectacle, ngraham
Subscribers: ngraham, nicolasfella, Spectacle
Tags: Spectacle
Differential Revision: https://phabricator.kde.org/D18609