mgr/orchestrator: block OSD specs with no service id
This is a copy of a code comment from this commit, but
it explains the change, so putting it here as well
There is a general "osd" service with no service id, but we use
that to dump osds created individually with "ceph orch daemon add osd"
and those made with "ceph orch apply osd --all-available-devices"
For actual user created OSD specs, we should promote users having a
service id so it doesn't get mixed in with those other OSDs. This
check is being done in this spot in particular as this is the only
place we can 100% differentiate between an actual user created OSD
spec and a spec we made ourselves to cover the all-available-devices case