ICE candidates are emitted asynchronously, so by the time that SDP messages have been exchanged, some remote candidates might have already arrived and stored in temporary variables. These candidates must be added to the PeerConnection, to make sure that none is left out! Corresponds to equivalent code in OpenVidu-Browser: https://github.com/OpenVidu/openvidu/blob/v2.20.0/openvidu-browser/src/OpenViduInternal/WebRtcPeer/WebRtcPeer.ts#L140-L148