With the new Wayland only mode we start too fast and it can happen that
the initWithWorkspace is called before the client connection is fully
setup. This would result in a crash in the idletime plugin once it tries
to create a seat.

To prevent this problem the code is split out into a dedicated method
and only invoked if all interfaces have been announced on the internal
connection.

BUG: 385397
FIXED-IN: 5.11.1