fix(RTCUtils) drop unnecessary variable

modules/RTC/RTC.js

      * @return {TraceablePeerConnection}
      */
     createPeerConnection(signaling, pcConfig, isP2P, options) {
-        const pcConstraints = cloneDeep(RTCUtils.pcConstraints);
+        const pcConstraints = {};
 
         if (options.enableInsertableStreams) {
             logger.debug('E2EE - setting insertable streams constraints');

modules/RTC/RTCUtils.js

                 });
         }
 
-        this.pcConstraints = {};
-
         screenObtainer.init(options);
 
         this.enumerateDevices(ds => {