List chat session history

curl --request GET \
  --url https://api.open.cx/chat/sessions/{session_id}/history \
  --header 'Authorization: Bearer <token>'

{
  "items": [
    {
      "created_at": "2023-11-07T05:31:56Z",
      "event": {
        "type": "message",
        "sender": {
          "type": "contact"
        },
        "content": {
          "type": "text",
          "text": "<string>"
        }
      }
    }
  ],
  "next": "<string>"
}