fix(tracks) Fix mobile safari issue with startMuted.

On mobile Safari, when a user joins both audio and video muted, browser doesn't playout the remote audio because of a webkit bug. As a workaround, always add the audio track to peerconnection and then mute the track if needed.

conference.js

     setAudioOutputDeviceId,
     updateDeviceList
 } from './react/features/base/devices';
+import { isIosMobileBrowser } from './react/features/base/environment/utils';
 import {
     browser,
     isFatalJitsiConnectionError,
         this._initDeviceList(true);
 
         if (initialOptions.startWithAudioMuted) {
-            localTracks = localTracks.filter(track => track.getType() !== MEDIA_TYPE.AUDIO);
+            // Always add the audio track to the peer connection and then mute the track on mobile Safari
+            // because of a known issue where audio playout doesn't happen if the user joins audio and video muted.
+            if (isIosMobileBrowser()) {
+                this.muteAudio(true, true);
+            } else {
+                localTracks = localTracks.filter(track => track.getType() !== MEDIA_TYPE.AUDIO);
+            }
         }
 
         return this.startConference(con, localTracks);
 
         APP.store.dispatch(conferenceWillJoin(room));
 
-        // Filter out the tracks that are muted.
-        const tracks = localTracks.filter(track => !track.isMuted());
+        // Filter out the tracks that are muted (except on mobile Safari).
+        const tracks = isIosMobileBrowser() ? localTracks : localTracks.filter(track => !track.isMuted());
 
         this._setLocalAudioVideoStreams(tracks);
         this._room = room; // FIXME do not use this
 
             // Remove the tracks from the peerconnection.
             for (const track of localTracks) {
-                if (audioMuted && track.jitsiTrack?.getType() === MEDIA_TYPE.AUDIO) {
+                // Always add the track on mobile Safari because of a known issue where audio playout doesn't happen
+                // if the user joins audio and video muted.
+                if (audioMuted && track.jitsiTrack?.getType() === MEDIA_TYPE.AUDIO && !isIosMobileBrowser()) {
                     promises.push(this.useAudioStream(null));
                 }
                 if (videoMuted && track.jitsiTrack?.getType() === MEDIA_TYPE.VIDEO) {

react/features/prejoin/middleware.js

 
 import { CONFERENCE_JOINED } from '../base/conference';
 import { updateConfig } from '../base/config';
-import { SET_AUDIO_MUTED, SET_VIDEO_MUTED } from '../base/media';
+import { isIosMobileBrowser } from '../base/environment/utils';
+import { MEDIA_TYPE, SET_AUDIO_MUTED, SET_VIDEO_MUTED } from '../base/media';
 import { MiddlewareRegistry } from '../base/redux';
 import { updateSettings } from '../base/settings';
 import {
 
         // Do not signal audio/video tracks if the user joins muted.
         for (const track of localTracks) {
-            if (track.muted) {
+            // Always add the audio track on mobile Safari because of a known issue where audio playout doesn't happen
+            // if the user joins audio and video muted.
+            if (track.muted
+                && !(isIosMobileBrowser() && track.jitsiTrack && track.jitsiTrack.getType() === MEDIA_TYPE.AUDIO)) {
                 await dispatch(replaceLocalTrack(track.jitsiTrack, null));
             }
         }