[Feedback]: Security endpoint management APIs do not mention how to obtain `file_id`

[rseldner]

The Download a file and Get file information APIs require the user to specify a {file_id} value but no instructions on how to obtain it

• https://www.elastic.co/docs/api/doc/kibana/operation/operation-endpointfiledownload
• https://www.elastic.co/docs/api/doc/kibana/operation/operation-endpointfileinfo

The related Response Actions API responses do not explicitly present such a value.
It would be helpful to mention users must construct it by combining the get-file action and agent ids. {file_id}={action_id}.{agent_id}