Add TODO in the Opus encoder where the application param is set

Bug: webrtc:376071290
Change-Id: Idd9017435bab9f8b53771c0dd642fd4ce3db048e
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/366981
Reviewed-by: Henrik Lundin <henrik.lundin@webrtc.org>
Commit-Queue: Alessio Bazzica <alessiob@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#43323}

modules/audio_coding/codecs/opus/audio_encoder_opus.cc

@@ -245,6 +245,7 @@ std::optional<AudioEncoderOpusConfig> AudioEncoderOpusImpl::SdpToConfig(
   config.bitrate_bps =
       CalculateBitrate(config.max_playback_rate_hz, config.num_channels,
                        GetFormatParameter(format, "maxaveragebitrate"));
+  // TODO: https://issues.webrtc.org/376071290 - Use `contentHint` if available.
   config.application = config.num_channels == 1
                            ? AudioEncoderOpusConfig::ApplicationMode::kVoip
                            : AudioEncoderOpusConfig::ApplicationMode::kAudio;