`telegraf` helm chart uses unexported ports for prometheus-client

[jcpunk]

When using prometheus to track the state of telegraf, a svc/telegraf is created that points to port 9126. However, the telegraf pod does not list that port.

kubectl -n telegraf get pod telegraf-6d666d97d8-jgr9x -o jsonpath='{.spec.containers[0].ports}'
kubectl -n telegraf get svc telegraf -o yaml

In my ideal world, this port would be added with a name: prometheus-client and that name used for the service.