shell: Assume consistency with the desktop roles

shell: Assume consistency with the desktop roles

While looking into activation by default of other surfaces, noticed that
we're missing consistency on how we handle other types of surface roles.

This patch, activate all other surfaces by default when starting up,
even if they are started before or after the client shell.
Expecting and assuming the same behaviour is important into trying
to establish some common work-flow for applications.

Bug-AGL: SPEC-3494

Signed-off-by: Marius Vlad <marius.vlad@collabora.com>
Change-Id: I90e764c6c3a7ed543934ee6f68fa716d90ff151e