Ensure puma and workhorse metrics are being collected for the webservice K8s pod

We appear to be missing metrics in k8s for workhorse:

https://thanos-query.ops.gitlab.net/graph?g0.range_input=1h&g0.max_source_resolution=0s&g0.expr=gitlab_workhorse_http_time_to_write_header_seconds_bucket%7Benv%3D%22gstg%22%2C%20type%3D%22git%22%7D&g0.tab=1

Before moving to canary, we should confirm that we collecting all relevant puma/workhorse metrics and they are labeled correctly.