The following scenario produced silence audio in egress
1. JS SDK publishing audio/red
2. Egress joins
3. Egress picks the RED primary receiver -> this converts RED to Opus in SFU
4. At the same time, codec regression is triggered back to the publisher. Publisher switches to publishing audio/opus and stops audio/red.
5. But, egress is still attached to audio/red and pulls down only silence.
Fix by checking if the negotiated codec needs publish before sending
subscribed codec udpate.