mgr: apply auth_service_required to client conns

mgr: apply auth_service_required to client conns

Previously was using auth_cluster_required for all
connections, which meant that if someone had
disabled client cephx, they'd get BADAUTHORIZER
from their CLI when it tried to load mgr
command descriptions.

Disabling cephx on the admin CLI is odd, but the mon
tolerates it so the mgr should too.

Fixes: https://tracker.ceph.com/issues/22096
Signed-off-by: John Spray <john.spray@redhat.com>