shrink-rgw.yml: fix confirmation play's name
shrink-rgw.yml: fix confirmation play's name

the confirmation play's name should confirm removing rgw instead of
monitor

Signed-off-by: Mehdy Khoshnoody <544474accde7964c713a06c1d639083c433b27c5@gmail.com>

ceph/ceph-ansible,ceph/ceph-ansible