fix(chart): correctly template actionsmetrics service ports

[chrisminton]

• currently setting the service ports via actionsMetricsServer.enabled: true gives:

  Warning  UpgradeFailed  2s  helm-controller  Helm upgrade failed for release namespace/actions-runner-controller with chart [email protected]: error while running post render on files: map[string]interface {}(nil): yaml: unmarshal errors:
  line 19: mapping key "name" already defined at line 15
  line 20: mapping key "port" already defined at line 16
  line 21: mapping key "protocol" already defined at line 17
  line 22: mapping key "targetPort" already defined at line 18
  

since the values.yaml already provides the key/values for the ports, just use toYaml which does correctly template the values. This change outputs (with the default values):

spec:
  type: ClusterIP
  ports:
    - name: http
      port: 80
      protocol: TCP
      targetPort: http