update: fix mgr upgrade issue

for some reason, this task has to be done in 2 steps otherwise it fails.
1/ stop and disable the service
2/ mask it

when done with with a single task, the module says the service has been
stopped while this isn't the case (Ansible systemd module bug?).

it possibly relates to https://github.com/ansible/ansible/issues/68680

Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>

infrastructure-playbooks/rolling_update.yml

@@ -391,6 +391,12 @@
         name: ceph-mgr@{{ ansible_facts['hostname'] }}
         state: stopped
         enabled: no
+        masked: no
+      failed_when: false
+
+    - name: mask ceph mgr systemd unit
+      systemd:
+        name: ceph-mgr@{{ ansible_facts['hostname'] }}
         masked: yes
       failed_when: false