added prometheus url to frontend

Author: Padraic-O-Mhuiris

internal/embed/defaults/helmfile.yaml

@@ -92,6 +92,8 @@ releases:
               value: "http://helios-{{ .Values.network }}.default.svc.cluster.local:8545"
             - name: NEXT_PUBLIC_ERPC_URL
               value: "http://erpc.default.svc.cluster.local:4000/rpc"
+            - name: NEXT_PUBLIC_PROMETHEUS_URL
+              value: "http://kube-prometheus-stack-prometheus.monitoring.svc.cluster.local:9090"
 
           repository: obolnetwork/obol-stack-front-end
           pullPolicy: IfNotPresent