Update password_config.yml

Signed-off-by: sakshiarora13 <sakshi_arora1@dell.com>

control_plane/roles/control_plane_common/tasks/password_config.yml

@@ -118,6 +118,7 @@
           - " \"'\" not in grafana_username "
           - grafana_password | length >= min_length_grafana
           - grafana_password | length <= max_length
+          - not grafana_password == 'admin'
           - '"-" not in grafana_password '
           - '"\\" not in grafana_password '
           - '"\"" not in grafana_password '