[Elastic Agent] Allow Metricbeat metricsets to report their status to the Elastic Agent

[cmacknz]

In #39735 a status reporter was passed into the Beats object reloader and propagated through to Filebeat inputs via the input V2 interface.

Identify how to propagate the status reporter into Metricbeat metricsets to allow them to report their status to the Elastic Agent when they encounter errors.

Choose a metricset to use as a reference implementation and have it report errors using the control protocol.

[elasticmachine]

Pinging @elastic/elastic-agent-data-plane (Team:Elastic-Agent-Data-Plane)

[cmacknz]

#39737 is an obvious candidate to do alongside this one, but we could also pick a metricset that requires a username/password combination as it will have a much clearer criteria for when to report the failed state.

[VihasMakwana]

@jlind23 @pierrehilbert attaching the screenshot of Kibana with a custom build.

[VihasMakwana]

Waiting on #40298

[VihasMakwana]

Screenshot of error event.