MetaWaylandSurface: Don't respond to frame callback when role unassigned

If a surface doesn't have a role, the compositor will not know how, if
or when it will be painted. By adding it to the compositor frame
callback list, the compositor will respond to the client that the
surface has been drawn already which might not be true.

Instead, queue the frame callback in a list that is then processed when
the surface gets a role assigned. The compositor may then, given the
role the surface got, queue the frame callback accordingly.

https://bugzilla.gnome.org/show_bug.cgi?id=744932