fix(prometheus): use alertmanager instance name

!8

templates/Prometheus-prometheus.yaml

@@ -16,7 +16,7 @@ spec:
   alerting:
     alertmanagers:
     - apiVersion: v2
-      name: alertmanager-main
+      name: alertmanager-{{ $.Release.Name }}
       namespace: "{{ .Values.nfc_monitoring.alert_manager.namespace }}"
       port: web
   enableFeatures: []