message: fix protocol integration test flake
diff: @@ -958,6 +958,7 @@ TEST_P(DownstreamProtocolIntegrationTest, ManyRequestHeadersAccepted) {
  TEST_P(DownstreamProtocolIntegrationTest, ManyRequestTrailersRejected) {
  // Default header (and trailer) count limit is 100.
  config_helper_.addConfigModifier(setEnableDownstreamTrailersHttp1());
  + config_helper_.addConfigModifier(setEnableUpstreamTrailersHttp1());
  Http::TestHeaderMapImpl request_trailers;
  for (int i = 0; i < 150; i++) {
  request_trailers.addCopy("trailer", std::string(1, 'a'));
  