feat(presenter): Modify the default behavior for presenter mode, it set to off when screensharing is turned on. Also, revert video to the original state when screensharing is turned off.

conference.js

                 await this.localVideo.setEffect(undefined);
                 APP.store.dispatch(
                     setVideoMuted(mute, MEDIA_TYPE.PRESENTER));
-                this._untoggleScreenSharing
-                    = this._turnScreenSharingOff.bind(this, false);
             } catch (err) {
                 logger.error('Failed to mute the Presenter video');
             }
         try {
             await this.localVideo.setEffect(effect);
             APP.store.dispatch(setVideoMuted(mute, MEDIA_TYPE.PRESENTER));
-            this._untoggleScreenSharing
-                = this._turnScreenSharingOff.bind(this, true);
         } catch (err) {
             logger.error('Failed to apply the Presenter effect', err);
         }
         }
 
         if (toggle) {
-            const wasVideoMuted = this.isLocalVideoMuted();
-
             try {
                 await this._switchToScreenSharing(options);
-            } catch (err) {
-                logger.error('Failed to switch to screensharing', err);
 
                 return;
-            }
-            if (wasVideoMuted) {
-                return;
-            }
-            const { height } = this.localVideo.track.getSettings();
-            const defaultCamera
-                = getUserSelectedCameraDeviceId(APP.store.getState());
-            let effect;
-
-            try {
-                effect = await this._createPresenterStreamEffect(
-                    height, defaultCamera);
             } catch (err) {
-                logger.error('Failed to create the presenter effect');
-
-                return;
-            }
-            try {
-                await this.localVideo.setEffect(effect);
-                muteLocalVideo(false);
-
-                return;
-            } catch (err) {
-                logger.error('Failed to create the presenter effect', err);
+                logger.error('Failed to switch to screensharing', err);
 
                 return;
             }
     _createDesktopTrack(options = {}) {
         let externalInstallation = false;
         let DSExternalInstallationInProgress = false;
-        const didHaveVideo = Boolean(this.localVideo);
+        const didHaveVideo = !this.isLocalVideoMuted();
 
         const getDesktopStreamPromise = options.desktopStream
             ? Promise.resolve([ options.desktopStream ])