feat(load-test): Load test startmuted (#8629)

* feat(load-test): Senders unmute themselves if muted by policy.

* feat(load-test): Adds option to skip creating local audio track.

We currently create local audio track even when starting audio muted. Adding the option to control that can load test that for clients or signalling.

resources/load-test/load-test-participant.js

     localVideo = config.startWithVideoMuted !== true,
     remoteVideo = isHuman,
     remoteAudio = isHuman,
-    autoPlayVideo = config.testing.noAutoPlayVideo !== true
+    autoPlayVideo = config.testing.noAutoPlayVideo !== true,
+
+    // Whether to create local audio even if muted
+    autoCreateLocalAudio = config.testing.noAutoLocalAudio !== true
 } = params;
 
 const { room: roomName } = parseURIString(window.location.toString());
     console.log('Conference joined');
 }
 
+/**
+ * Handles start muted events, when audio and/or video are muted due to
+ * startAudioMuted or startVideoMuted policy.
+ */
+function onStartMuted() {
+    // Give it some time, as it may be currently in the process of muting
+    setTimeout(() => {
+        const localAudioTrack = room.getLocalAudioTrack();
+
+        if (localAudio && localAudioTrack && localAudioTrack.isMuted()) {
+            localAudioTrack.unmute();
+        }
+
+        const localVideoTrack = room.getLocalVideoTrack();
+
+        if (localVideo && localVideoTrack && localVideoTrack.isMuted()) {
+            localVideoTrack.unmute();
+        }
+    }, 2000);
+}
+
 /**
  *
  * @param id
  */
 function onConnectionSuccess() {
     room = connection.initJitsiConference(roomName.toLowerCase(), config);
+    room.on(JitsiMeetJS.events.conference.STARTED_MUTED, onStartMuted);
     room.on(JitsiMeetJS.events.conference.TRACK_ADDED, onRemoteTrack);
     room.on(JitsiMeetJS.events.conference.CONFERENCE_JOINED, onConferenceJoined);
     room.on(JitsiMeetJS.events.conference.USER_JOINED, id => {
     if (localVideo) {
         devices.push('video');
     }
-    devices.push('audio');
+
+    if (autoCreateLocalAudio) {
+        devices.push('audio');
+    }
 
     if (devices.length > 0) {
         JitsiMeetJS.createLocalTracks({ devices })