message: fix: Dashboad export loading indicator
diff: @@ -722,9 +722,9 @@ class DashboardRestApi(BaseSupersetModelRestApi):
  $ref: '#/components/responses/500'
  """
  requested_ids = kwargs["rison"]
  + token = request.args.get("token")
  if is_feature_enabled("VERSIONED_EXPORT"):
  - token = request.args.get("token")
  timestamp = datetime.now().strftime("%Y%m%dT%H%M%S")
  root = f"dashboard_export_{timestamp}"
  filename = f"{root}.zip"
  @@ -763,6 +763,8 @@ class DashboardRestApi(BaseSupersetModelRestApi):
  resp.headers["Content-Disposition"] = generate_download_headers("json")[
  "Content-Disposition"
  ]
  + if token:
  + resp.set_cookie(token, "done", max_age=600)
  return resp
  @expose("/<pk>/thumbnail/<digest>/", methods=["GET"])
  