Fix web_exporter log events for GME

For some reason, GME isn't logging anything on Puma nodes: https://nonprod-log.gitlab.net/goto/a49a62e0-8b71-11ed-9af2-6131f0ee4ce6. It should be logging via the web_exporter subcomponent.

It is not a problem with the Rails monitoring config in gitlab.yml because this is shared between GME and the Ruby exporters, and they do emit log events.