ios: don't override AVAudioSession category and mode in default state
ios: don't override AVAudioSession category and mode in default state

When we are in the default state (ie, not in a meeting) we shouldn't override
the AVAudioSession category and mode. It's a singleton and we might be bothering
other components of the host app which use it.

jitsi/jitsi-meet,gpolitis/jitsi-meet,gpolitis/jitsi-meet,gpolitis/jitsi-meet,gpolitis/jitsi-meet,bgrozev/jitsi-meet,jitsi/jitsi-meet,gpolitis/jitsi-meet,jitsi/jitsi-meet,bgrozev/jitsi-meet,jitsi/jitsi-meet,bgrozev/jitsi-meet,gpolitis/jitsi-meet,gpolitis/jitsi-meet,jitsi/jitsi-meet,bgrozev/jitsi-meet,bgrozev/jitsi-meet,bgrozev/jitsi-meet,jitsi/jitsi-meet,jitsi/jitsi-meet,jitsi/jitsi-meet,gpolitis/jitsi-meet