List Workflow Instances

curl --request GET \
  --url https://api.example.com/api/v1/workflows/{workflow_id}/instances

{
  "items": [
    {
      "id": "<string>",
      "workflow_id": "<string>",
      "account_id": "<string>",
      "status": "<string>",
      "current_step": "<string>",
      "context": {},
      "started_at": "2023-11-07T05:31:56Z",
      "completed_at": "2023-11-07T05:31:56Z",
      "error_message": "<string>",
      "resume_job_id": "<string>"
    }
  ],
  "total": 123
}