templates do not render usable concourse-web-prometheus service

After deploying helm chart in --debug --dry-run mode, the service is rendered:

---
# Source: concourse/templates/web-prometheus-svc.yaml
apiVersion: v1
kind: Service
metadata:
  name: concourse-web-prometheus
  labels:
    app: concourse-web
    chart: "concourse-14.0.3"
    release: "concourse"
    heritage: "Helm"
  annotations:
    prometheus.io/scrape: "true"
    prometheus.io/port: "9391"
spec:
  type: ClusterIP
  ports:
    - name: prometheus
      port: 9391
      targetPort: prometheus
  selector:
    app: concourse-web

Which produces the following service:

kubectl get services
NAME                            TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)          AGE
concourse-postgresql            ClusterIP   None             <none>        5432/TCP         44h
concourse-postgresql-headless   ClusterIP   None             <none>        5432/TCP         44h
concourse-web                   NodePort    172.20.250.183   <none>        8080:30001/TCP   19m
concourse-web-prometheus        ClusterIP   172.20.253.78    <none>        9391/TCP         10m
concourse-web-worker-gateway    NodePort    172.20.115.171   <none>        2222:30002/TCP   44h
concourse-worker                ClusterIP   None             <none>        <none>           44h
kubernetes                      ClusterIP   172.20.0.1       <none>        443/TCP          2d

However a loadbalancer cannot be connected to the ClusterIP 172.20.253.78, because it's on a non-routable network.

Instead the templates need to be able to render a NodePort service, such as:

---
# Source: concourse/prometheus-svc.yml
apiVersion: v1
kind: Service
metadata:
  name: concourse-web-prometheus
  labels:
    app: concourse-web
    chart: "concourse-14.0.3"
    release: "concourse"
    heritage: "Helm"
  annotations:
    prometheus.io/scrape: "true"
    prometheus.io/port: "9391"
spec:
  type: NodePort
  ports:
  - name: prometheus
    port: 9391
    targetPort: prometheus
    nodePort: 30003
  selector:
    app: concourse-web

The following updates to the template templates/web-prometheus-svc.yaml spec: section render the proper service yaml code:

spec:
  type: {{ .Values.web.service.prometheus.type }}
  {{- if .Values.web.service.prometheus.loadBalancerSourceRanges }}
  loadBalancerSourceRanges:
    {{- range .Values.web.service.prometheus.loadBalancerSourceRanges }}
    - {{ . }}
    {{- end }}
  {{- end }}
  {{- if and (eq "ClusterIP" .Values.web.service.prometheus.type) .Values.web.service.prometheus.clusterIP }}
  clusterIP: {{ .Values.web.service.prometheus.clusterIP }}
  {{- end }}
  {{- if and (eq "LoadBalancer" .Values.web.service.prometheus.type) .Values.web.service.prometheus.loadBalancerIP }}
  loadBalancerIP: {{ .Values.web.service.prometheus.loadBalancerIP }}
  {{- end }}
  ports:
  - name: prometheus
    port: {{ .Values.concourse.web.prometheus.bindPort }}
    targetPort: prometheus
    {{- if and (eq "NodePort" .Values.web.service.prometheus.type) .Values.web.service.prometheus.NodePort }}
    nodePort: {{ .Values.web.service.prometheus.NodePort}}
    {{- end }}
  selector:
    app: {{ template "concourse.web.fullname" . }}

Here is the result after modifying the template as above, and supplying these values:
deployment-values.yml:

web:
  replicas: 3
  service:
    api:
      type: NodePort
      atcNodePort: 30008
      NodePort: 30001
    workerGateway:
      type: NodePort
      NodePort: 30002
    prometheus:
      type: NodePort
      NodePort: 30003

kubectl get services
NAME                            TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)          AGE
concourse-postgresql            ClusterIP   None             <none>        5432/TCP         45h
concourse-postgresql-headless   ClusterIP   None             <none>        5432/TCP         45h
concourse-web                   NodePort    172.20.250.183   <none>        8080:30001/TCP   71m
concourse-web-prometheus        NodePort    172.20.152.48    <none>        9391:30003/TCP   11s
concourse-web-worker-gateway    NodePort    172.20.115.171   <none>        2222:30002/TCP   45h
concourse-worker                ClusterIP   None             <none>        <none>           45h
kubernetes                      ClusterIP   172.20.0.1       <none>        443/TCP          2d1h

Start with templates/web-prometheus-svc.yaml and the web.service.prometheus values used by the Helm chart. Run a --debug --dry-run deployment with the provided NodePort values and compare the rendered service with the expected YAML. Done means the Prometheus service can render as a NodePort with the requested nodePort while retaining the existing ClusterIP behavior.