Creates FormField Positions

curl --request POST \
  --url https://api.rootly.com/v1/form_fields/{form_field_id}/positions \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/vnd.api+json' \
  --data '{
  "data": {
    "type": "form_field_positions",
    "attributes": {
      "form_field_id": "<string>",
      "form": "web_new_incident_form",
      "position": 123
    }
  }
}'

{
  "data": {
    "id": "6a357b7a-389b-4ba9-bfd3-a7a483024c9b",
    "type": "form_field_positions",
    "attributes": {
      "form_field_id": "5ae71e51-41dd-473e-bda2-c2c644e69f2b",
      "form": "web_new_incident_form",
      "position": 2
    }
  }
}