fix(JitsiTrack): set video element src to empty string instead of null on #detach()
fix(JitsiTrack): set video element src to empty string instead of null on #detach()

Setting the `src` of a video element to null triggered a network request for resource "null".

dmurtari/lib-jitsi-meet,jiyeyuran/lib-jitsi-meet,nevermind-corp/ljm,damencho/lib-jitsi-meet,adambowles/lib-jitsi-meet,dmurtari/lib-jitsi-meet,adambowles/lib-jitsi-meet,jitsi/lib-jitsi-meet,jitsi/lib-jitsi-meet