[REQUEST]: Show agentless resources toggle

[jen-huang]

Description

Documentation for the newly added "Show agentless resources" toggle in Fleet > Settings: elastic/kibana#237528

Resources

https://github.com/elastic/ingest-dev/issues/5932
elastic/kibana#237528

Collaboration

The documentation team will investigate the issue and create the initial content.

Point of contact.

Main contact: @jen-huang

Stakeholders: @nimarezainia @kpollich