New request component turn_attribution

{
  "har.send_payload_keys": [
    "action",
    "client_contextual_info",
    "client_prepare_state",
    "is_do_not_remember",
    "local_function_names",
    "messages",
    "model",
    "parent_message_id",
    "supported_encodings",
    "timezone",
    "timezone_offset_min",
    "turn_attribution"
  ]
}