Correct track replacement when resuming local track upstream (#1157)

* Correct track replacement when resuming upstream

- This should prevent replacing the processed track with the unprocessed
  track, if a track processor was applied while the track upstream was
  paused.

* Create kind-nails-battle.md

---------

Co-authored-by: lukasIO <mail@lukasseiler.de>

.changeset/kind-nails-battle.md

@@ -0,0 +1,5 @@
+---
+"livekit-client": patch
+---
+
+Fix resumeUpstream with local track processors enabled

src/room/track/LocalTrack.ts

@@ -433,7 +433,7 @@ export default abstract class LocalTrack<
       this.emit(TrackEvent.UpstreamResumed, this);
 
       // this operation is noop if mediastreamtrack is already being sent
-      await this.sender.replaceTrack(this._mediaStreamTrack);
+      await this.sender.replaceTrack(this.mediaStreamTrack);
     } finally {
       unlock();
     }