ref(TPC) Remove an unused method.

modules/RTC/TraceablePeerConnection.js

@@ -1683,23 +1683,6 @@ TraceablePeerConnection.prototype._mungeCodecOrder = function(description) {
     });
 };
 
-/**
- * Checks if given track belongs to this peerconnection instance.
- *
- * @param {JitsiLocalTrack|JitsiRemoteTrack} track - The track to be checked.
- * @returns {boolean}
- */
-TraceablePeerConnection.prototype.containsTrack = function(track) {
-    if (track.isLocal()) {
-        return this.localTracks.has(track.rtcId);
-    }
-
-    const participantId = track.getParticipantId();
-    const remoteTracksMap = this.remoteTracks.get(participantId);
-
-    return Boolean(remoteTracksMap && remoteTracksMap.get(track.getType()) === track);
-};
-
 /**
  * Add {@link JitsiLocalTrack} to this TPC.
  * @param {JitsiLocalTrack} track