roster: 'Add new contact' action isn't displayed on desktop
In some window sizes the button isn't displayed at all; if I resize the window (so that there's only this page visible) the button appears again.
This commit caused it: https://git.kaidan.im/kaidan/kaidan/commit/a46265e34258272c73b95b8ef287927ce2dc9842 (but it's a bug in Kirigami).
(Affected page: https://git.kaidan.im/kaidan/kaidan/blob/master/src/qml/RosterPage.qml)