fix(Thumbnail): volume & audioLevel default values

react/features/audio-level-indicator/components/AudioLevelIndicator.js

      * @returns {ReactElement}
      */
     render() {
+        const { audioLevel: passedAudioLevel } = this.props;
+
         // First make sure we are sensitive enough.
-        const audioLevel = Math.min(this.props.audioLevel * 1.2, 1);
+        const audioLevel = typeof passedAudioLevel === 'number' && !isNaN(passedAudioLevel)
+            ? Math.min(passedAudioLevel * 1.2, 1) : 0;
 
         // Let's now stretch the audio level over the number of dots we have.
         const stretchedAudioLevel = AUDIO_LEVEL_DOTS * audioLevel;

react/features/filmstrip/components/web/Thumbnail.js

             _videoTrack
         } = this.props;
         const { id } = _participant || {};
-        const { audioLevel = 0 } = this.state;
+        const { audioLevel } = this.state;
 
 
         return (
             _startSilent
         } = this.props;
         const { id } = _participant;
-        const { audioLevel = 0, volume = 1 } = this.state;
+        const { audioLevel, volume } = this.state;
 
         // hide volume when in silent mode
         const onVolumeChange = _startSilent ? undefined : this._onVolumeChange;

react/features/remote-video-menu/components/web/RemoteVideoMenuTriggerButton.js

      * A value between 0 and 1 indicating the volume of the participant's
      * audio element.
      */
-    initialVolumeValue: number,
+    initialVolumeValue: ?number,
 
     /**
      * Callback to invoke when changing the level of the participant's
                 participantID = { participantID } />
         );
 
-        if (onVolumeChange) {
+        if (onVolumeChange && initialVolumeValue && !isNaN(initialVolumeValue)) {
             buttons.push(
                 <VolumeSlider
                     initialValue = { initialVolumeValue }