curl --request GET \
  --url https://api.utage-system.com/v1/accounts/{account_id}/line/friends/{friend_id} \
  --header 'Authorization: Bearer <token>'

{
  "data": {
    "id": "<string>",
    "common_friend_id": "<string>",
    "common_reader_id": "<string>",
    "display_name": "<string>",
    "picture_url": "<string>",
    "is_blocked": true,
    "is_test_account": true,
    "is_exclusion": true,
    "response_status": {
      "text": "<string>",
      "color": "<string>"
    },
    "labels": [
      {
        "id": "<string>",
        "name": "<string>"
      }
    ],
    "common_fields": {},
    "memo": "<string>",
    "message_tracking_name": "<string>",
    "last_acted_at": "<string>",
    "created_at": "<string>"
  }
}