fix (external-api): fix notify video mute changed when presenting

- small refactor to trigger `notifyVideoMutedStatusChanged` correctly when participant is presenting

conference.js

         }
 
         if (!tracks.find(t => t.isVideoTrack())) {
-            this.setVideoMuteStatus(true);
+            this.setVideoMuteStatus();
         }
 
         if (config.iAmRecorder) {
             // This will only modify base/media.video.muted which is then synced
             // up with the track at the end of local tracks initialization.
             muteLocalVideo(mute);
-            this.setVideoMuteStatus(mute);
+            this.setVideoMuteStatus();
 
             return;
         } else if (this.isLocalVideoMuted() === mute) {
                     .then(() => {
                         this.localVideo = newTrack;
                         this._setSharingScreen(newTrack);
-                        this.setVideoMuteStatus(this.isLocalVideoMuted());
+                        this.setVideoMuteStatus();
                     })
                     .then(resolve)
                     .catch(error => {
             try {
                 await this.localVideo.setEffect(effect);
                 APP.store.dispatch(setVideoMuted(mute, MEDIA_TYPE.PRESENTER));
-                this.setVideoMuteStatus(mute);
+                this.setVideoMuteStatus();
             } catch (err) {
                 logger.error('Failed to apply the Presenter effect', err);
             }
                     return this._createPresenterStreamEffect(height, cameraDeviceId)
                         .then(effect => this.localVideo.setEffect(effect))
                         .then(() => {
-                            this.setVideoMuteStatus(false);
+                            this.setVideoMuteStatus();
                             logger.log('Switched local video device while screen sharing and the video is unmuted');
                             this._updateVideoDeviceId();
                         })
 
     /**
      * Sets the video muted status.
-     *
-     * @param {boolean} muted - New muted status.
      */
-    setVideoMuteStatus(muted) {
+    setVideoMuteStatus() {
         APP.UI.setVideoMuted(this.getMyUserId());
-        APP.API.notifyVideoMutedStatusChanged(muted);
     },
 
     /**

react/features/base/tracks/middleware.js

                 if (jitsiTrack.type === MEDIA_TYPE.PRESENTER) {
                     APP.conference.mutePresenter(muted);
                 } else if (jitsiTrack.isLocal()) {
-                    APP.conference.setVideoMuteStatus(muted);
+                    APP.conference.setVideoMuteStatus();
                 } else {
                     APP.UI.setVideoMuted(participantID);
                 }

react/features/base/tracks/subscriber.js

 
 import { StateListenerRegistry } from '../../base/redux';
 
+import { isLocalCameraTrackMuted } from './functions';
+
 declare var APP: Object;
 
 /**
         }
     }
 );
+
+
+/**
+ * Notifies when the local video mute state changes.
+ */
+StateListenerRegistry.register(
+    /* selector */ state => isLocalCameraTrackMuted(state['features/base/tracks']),
+    /* listener */ (muted, store, previousMuted) => {
+        if (typeof APP !== 'object') {
+            return;
+        }
+
+        if (muted !== previousMuted) {
+            APP.API.notifyVideoMutedStatusChanged(muted);
+        }
+    }
+);