Setting Default filter chain but no common filter chains should not "no filter chains specified" exception

[lambdai]

void ListenerImpl::validateFilterChains(Network::Socket::Type socket_type) {
  if (config_.filter_chains().empty() && (socket_type == Network::Socket::Type::Stream ||
                                          !udp_listener_factory_->isTransportConnectionless())) {
    // If we got here, this is a tcp listener or connection-oriented udp listener, so ensure there
    // is a filter chain specified
    throw EnvoyException(fmt::format("error adding listener '{}': no filter chains specified",
                                     address_->asString()));

Work around: create a never hit filter chain in listener.

Need to add tests coverage also validate that the rest of the code could tolerate empty common filter chain collection.

[lambdai]

The latter case could be

  if (PROTOBUF_GET_WRAPPED_OR_DEFAULT(config_.filter_chains()[0], use_proxy_proto, false)) {

[shashankram]

Has this fix made it into any envoy release yet? Will this be a part of 1.16.x or 1.17?
Thanks