message: fix(models/rest): unique key for form data item
diff: @@ -319,9 +319,7 @@ export class RESTManager {
  }
  }
  const form = new FormData()
  - for (const file of files) {
  - form.append(file.name, file.blob, file.name)
  - }
  + files.map((file, index) => form.append(`file${index + 1}`, file.blob, file.name))
  const json = JSON.stringify(body)
  form.append('payload_json', json)
  if (body === undefined) body = {}
  