fix(JitsiLocalTrack): report no data only when 'muted' is true

When the Temasys plugin is used the 'muted' property is in the track,
but it's value is undefined.

modules/RTC/JitsiLocalTrack.js

@@ -635,7 +635,7 @@ JitsiLocalTrack.prototype._isReceivingData = function () {
     // creation.
     return this.stream.getTracks().some(track =>
         ((!("readyState" in track) || track.readyState === "live")
-            && (!("muted" in track) || track.muted === false)));
+            && (!("muted" in track) || track.muted !== true)));
 };
 
 module.exports = JitsiLocalTrack;