Fix YAML document separator in operator RBAC

Helm doesn't render webhook `ClusterRole` if
`clustermongodbroles` RBAC is not rendered due to
`operator.enableClusterMongoDBRoles` being set to `false`.

Author: m1kola

helm_chart/templates/operator-roles.yaml

@@ -142,9 +142,9 @@ subjects:
     namespace: {{ include "mongodb-kubernetes-operator.namespace" $ }}
 {{- end }}
 
----
 
 {{- if .Values.operator.enableClusterMongoDBRoles }}
+---
 kind: ClusterRole
 apiVersion: rbac.authorization.k8s.io/v1
 metadata: