The RTCRtpSender needs to ensure that the transport identity matches the media track requested identity.
This is only done currently when changing the track:
"If withTrack.kind differs from RTCRtpSender.track.kind or if withTrack has different peerIdentity constraints, then reject p with IncompatibleMediaStreamTrackError and abort these steps. "
but it is not checked when the transport is changed.
When the transport is changed, the transport identity has to be checked against the media track constraints and if not matching, either raise an IncompatibleMediaStreamTrackError or return a promise and reject it.