Get the preview

curl --request GET \
  --url https://app.vern.so/api/v1/migrations/{migration_id}/preview \
  --header 'x-api-key: <api-key>'

{
  "status": "awaiting_approval",
  "templates": [
    {
      "slug": "contacts",
      "name": "Contacts"
    }
  ],
  "sheets": [
    {
      "template": {
        "slug": "contacts",
        "name": "Contacts"
      },
      "rows": [
        [
          "Email",
          "First Name",
          "Last Name"
        ],
        [
          "jane@acme.com",
          "Jane",
          "Doe"
        ]
      ],
      "invalid_cells": []
    }
  ]
}