community/qt5-qtwayland: use wayland-libs-server instead of wayland-libs-client

it's pretty impossible to have a wayland session without using the
server libraries, and things can pull in -client libraries even without
a session being available, so this pulled in qt5-qtwayland even when
someone for instance did apk add qt5-qtbase ffmpeg-libs (because
ffmpeg-libs->libva->wayland-libs-client), which is possible on a server