Lazily initialize and destroy the audio handle state on call initiation and end

crates/call/src/call.rs

@@ -5,6 +5,7 @@ pub mod room;
 use std::sync::Arc;
 
 use anyhow::{anyhow, Result};
+use audio::Audio;
 use call_settings::CallSettings;
 use client::{
     proto, ChannelId, ClickhouseEvent, Client, TelemetrySettings, TypedEnvelope, User, UserStore,
@@ -309,6 +310,7 @@ impl ActiveCall {
     pub fn hang_up(&mut self, cx: &mut ModelContext<Self>) -> Task<Result<()>> {
         cx.notify();
         self.report_call_event("hang up", cx);
+        Audio::end_call(cx);
         if let Some((room, _)) = self.room.take() {
             room.update(cx, |room, cx| room.leave(cx))
         } else {