Don't SetCodecPreferences for video transceiver (#3249)

The SetCodecPrefrences function will save codecs
to the transceiver and if the primary codec is not
support by the client, the saved codec will generate
rtx codec for the unsupported codec cause corrupted
sdp.

pkg/rtc/transport.go

@@ -811,7 +811,9 @@ func (t *PCTransport) AddTrack(trackLocal webrtc.TrackLocal, params types.AddTra
 		return
 	}
 
-	configureAudioTransceiver(transceiver, params.Stereo, !params.Red || !t.params.ClientInfo.SupportsAudioRED())
+	if trackLocal.Kind() == webrtc.RTPCodecTypeAudio {
+		configureAudioTransceiver(transceiver, params.Stereo, !params.Red || !t.params.ClientInfo.SupportsAudioRED())
+	}
 	return
 }
 
@@ -827,7 +829,9 @@ func (t *PCTransport) AddTransceiverFromTrack(trackLocal webrtc.TrackLocal, para
 		return
 	}
 
-	configureAudioTransceiver(transceiver, params.Stereo, !params.Red || !t.params.ClientInfo.SupportsAudioRED())
+	if trackLocal.Kind() == webrtc.RTPCodecTypeAudio {
+		configureAudioTransceiver(transceiver, params.Stereo, !params.Red || !t.params.ClientInfo.SupportsAudioRED())
+	}
 
 	return
 }