message: Add commas between codec parameters in VideoReceiveStream logging.
  Meaning you'll see "{foo: 1, bar: 2}" instead of "{foo: 1bar: 2}".
  Cr-Commit-Position: refs/heads/master@{#30717}
diff: @@ -24,8 +24,13 @@ std::string VideoReceiveStream::Decoder::ToString() const {
  ss << "{payload_type: " << payload_type;
  ss << ", payload_name: " << video_format.name;
  ss << ", codec_params: {";
  - for (const auto& it : video_format.parameters)
  - ss << it.first << ": " << it.second;
  + for (auto it = video_format.parameters.begin();
  + it != video_format.parameters.end(); ++it) {
  + if (it != video_format.parameters.begin()) {
  + ss << ", ";
  + }
  + ss << it->first << ": " << it->second;
  + }
  ss << '}';
  ss << '}';
  