fix: remove undefined variable

Author: ntk148v

ansible/roles/alertmanager/handlers/main.yml

@@ -27,5 +27,4 @@
     - inventory_hostname in groups[service.group]
     - service.enabled | bool
     - alertmanager_config.changed | bool
-      or alertmanager_custom_confs.changed | bool
       or alertmanager_custom_templates.changed | bool