cadf resource id omit empty

[notque]

In a specific case, we are renaming the id to be project_id now for multiple reasons.

if [target][id] and [target][typeURI] == "data/security/project" {
    mutate {
      id => "f06c_move_target_id_to_project_id"
      add_field => { "[target][project_id]" => "%{[target][id]}" }
      remove_field => [ "[target][id]" ]
    }
  }

This means that we need to make ID omitempty as we remove id when it moves to project_id in cases this occurs.

I can't think of any issues with doing this. If it doesn't exist, it shouldn't be returned.