curl --request GET \
  --url http://localhost:8000/api/v1/campaigns/drafts/{draft_id}/generation-status \
  --header 'Authorization: Bearer <token>'

{
  "ad_groups": {
    "task_id": "<string>",
    "status": "not_started",
    "error": "<string>"
  },
  "rsas": [
    {
      "rsa_id": 123,
      "ad_group_id": 123,
      "task_id": "<string>",
      "status": "not_started",
      "error": "<string>"
    }
  ],
  "extensions": {
    "task_id": "<string>",
    "status": "not_started",
    "error": "<string>"
  },
  "all_complete": true
}