From Jen in comment:

@kilfoyle We need to consolidate or duplicate the information on these two pages somehow:

https://www.elastic.co/guide/en/fleet/current/elastic-agent-monitoring-configuration.html

https://www.elastic.co/guide/en/fleet/current/agent-policy.html#change-policy-enable-agent-monitoring

With this PR, all the options from the first page are now available to be configured in the UI.

Based on the original issue description, elastic/kibana#153950 (comment), it seems the first page is not capturing all the available options under agent.monitoring either.

When this is done we also need to remove this section in favor of whatever documentation is added about the full advance monitoring options:
https://www.elastic.co/guide/en/fleet/current/agent-policy.html#agent-policy-http-monitoring

Planned for 8.16
Jen will need an updated URL for the UI link.