message: config: optimize RepeatedPtrUtil::debugString at non-debug log levels.
  This one was showing up on our flamegraphs.
  Risk Level: Low
  Testing: bazel build //source/exe/...
diff: @@ -55,9 +55,11 @@ public:
  stats_.update_attempt_.inc();
  version_info_ = version_info;
  stats_.version_.set(HashUtil::xxHash64(version_info_));
  + if (ENVOY_LOG_CHECK_LEVEL(debug)) {
  ENVOY_LOG(debug, "gRPC config for {} accepted with {} resources: {}", type_url_,
  resources.size(), RepeatedPtrUtil::debugString(typed_resources));
  }
  + }
  void onConfigUpdateFailed(const EnvoyException* e) override {
  // TODO(htuch): Less fragile signal that this is failure vs. reject.
  