webrtcbin should ignore some fields when answering
When intersecting local codec-preference caps with a peer's SDP, webrtcbin should ignore some fields depending on the codec.
For example, with Opus, mismatched sprop-stereo
or sprop-maxcapturerate
fields can lead to a failure to negotiate a sendrecv media, even though the fields are purely informative from the sender side as per https://datatracker.ietf.org/doc/html/rfc7587#section-7.1
_create_answer_task:<sendrecv> did not find compatible transceiver for offer caps application/x-rtp, media=(string)audio, payload=(int)97, clock-rate=(int)48000, encoding-name=(string)OPUS, encoding-params=(string)2, sprop-stereo=(string)0, sprop-maxcapturerate=(string)48000, rtcp-fb-transport-cc=(boolean)true, will only receive