ceph-volume: allow zapping partitions on multipath devices

ceph-volume: allow zapping partitions on multipath devices

ceph-volume refuses to zap a device if it is a partition on a multipath
device due to an overly strict condition. This change ensures that only
full mapper devices (excluding partitions) are blocked from being zapped,
allowing partitions on multipath devices to be processed correctly.

Fixes: https://tracker.ceph.com/issues/70363
Signed-off-by: Guillaume Abrioux <gabrioux@ibm.com>
(cherry picked from commit 16daa6a687c0536324b06536af12ce4e8fc04087)
(cherry picked from commit 29b6bcda3f69f594a751ec92b6985b3dfdd4d56b)