Fix joining call with audio and video muted

src/state/PublishConnection.ts

@@ -109,10 +109,15 @@ export class PublishConnection extends Connection {
 
     if (this.stopped) return;
 
-    // TODO this can throw errors? It will also prompt for permissions if not already granted
+    // TODO-MULTI-SFU: Prepublish a microphone track
+    const audio = this.muteStates.audio.enabled$.value;
+    const video = this.muteStates.video.enabled$.value;
+    // createTracks throws if called with audio=false and video=false
+    if (audio || video) {
+      // TODO this can still throw errors? It will also prompt for permissions if not already granted
       const tracks = await this.livekitRoom.localParticipant.createTracks({
-      audio: this.muteStates.audio.enabled$.value,
-      video: this.muteStates.video.enabled$.value,
+        audio,
+        video,
       });
       if (this.stopped) return;
       for (const track of tracks) {
@@ -123,6 +128,7 @@ export class PublishConnection extends Connection {
         // TODO: check if the connection is still active? and break the loop if not?
       }
     }
+  }
 
   public async stop(): Promise<void> {
     // TODO-MULTI-SFU: Move these calls back to ObservableScope.onEnd once scope