fix(JitsiTrack): Remove func that's no longer used.

modules/RTC/JitsiLocalTrack.js

      */
     _setStream(stream) {
         super._setStream(stream);
-
-        if (stream) {
-            // Store the MSID for video mute/unmute purposes.
-            this.storedMSID = this.getMSID();
-            logger.debug(`Setting new MSID: ${this.storedMSID} on ${this}`);
-        } else {
-            logger.debug(`Setting 'null' stream on ${this}`);
-        }
     }
 
     /**

modules/RTC/JitsiTrack.js

         return this.getStreamId();
     }
 
-    /**
-     * Returns the msid of the stream attached to the JitsiTrack object or null
-     * if no stream is attached.
-     */
-    getMSID() {
-        const streamId = this.getStreamId();
-        const trackId = this.getTrackId();
-
-        return streamId && trackId ? `${streamId} ${trackId}` : null;
-    }
-
     /**
      * Returns the WebRTC MediaStream instance.
      */

types/hand-crafted/modules/RTC/JitsiTrack.d.ts

   getId: () => string | null;
   isActive: () => boolean;
   setAudioLevel: ( audioLevel: number, tpc: TraceablePeerConnection ) => void;
-  getMSID: () => string | null;
   setAudioOutput: ( audioOutputDeviceId: '' | string ) => Promise<unknown>; // TODO: what will this promise contain?
   addEventListener: (type: string, listener: (event: any) => void) => void;
 }