fix(ChatRoom): rename 'bridgeIsDown' and it's ext name
fix(ChatRoom): rename 'bridgeIsDown' and it's ext name

The corresponding extension's name was changed
in Jicofo to 'bridgeNotAvailable'.

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