Fix misplacement of Contract attribute "Fecha_planificada_de_entrega"

Fix https://gitlab.com/coopdevs/pymasmovil/-/merge_requests/87

MM order item structure retreived by curl:

    {
      "accountId": "0014I00002AL3A7QAL",
      "additionalBonds": [
        {
          ...
        }
      ],
      "attributes": {
       ...
      },
      "createdDate": "2021-07-21T07:11:56.000Z",
      "detalleEstado": "Enviada",
      "fechaPortabilidad": "2021-07-23T02:00:00",
      "id": "xxxxx",
      "orderType": "Alta",
      "phone": "XXXXX",
      "productId": "01t4I000006bWYzQAM",
      "productName": "Tarifa Ilimitada Voz Total Nov19",
      "simAttributes": {
        ...
      },
      "status": "Enviada",
      "tarAttributes": {
        "Fecha_planificada_de_entrega": "2021-07-23",
        "Fecha_planificada_de_solicitud_de_portabilidad": null
      },
      "transactionId": "000000000000000484"
    }