curl --request GET \
  --url https://api.landing.ai/v1/projects/{project_id}/metadata

{
  "data": [
    {
      "name": "<string>",
      "type": "text",
      "allowMultiple": true,
      "predefinedChoices": [
        "<string>"
      ],
      "id": 123,
      "valueFlexible": true
    }
  ]
}