curl --request POST \
  --url http://localhost:3001/api/admin/content/templates/test \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "workspaceId": "<string>",
  "templateId": "<string>",
  "userProperties": {},
  "tags": {}
}
'

{
  "value": {
    "variant": {
      "provider": {},
      "to": "<string>",
      "from": "<string>",
      "subject": "<string>",
      "body": "<string>",
      "headers": {},
      "attachments": [
        {
          "mimeType": "<string>",
          "name": "<string>"
        }
      ],
      "replyTo": "<string>",
      "cc": "<string>",
      "bcc": "<string>",
      "name": "<string>",
      "attachmentUserProperties": [
        "<string>"
      ]
    }
  }
}