message: show better 404 message for unknown provider endpoints
diff: @@ -144,6 +144,11 @@ export async function createRouter({
  }
  }
  + router.use('/:provider/', req => {
  + const { provider } = req.params;
  + throw new NotFoundError(`Unknown auth provider '${provider}'`);
  + });
  +
  router.use(
  createOidcRouter({
  tokenIssuer,
  