Delete left-over call to RegisterPacketRequestCallback

The unregister call was overlooked in
https://webrtc-review.googlesource.com/c/src/+/133189

Bug: webrtc:7408
Change-Id: Ida4702187a1cdf08cf3326b57da5e8dc7a5c5aed
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/133563
Reviewed-by: Åsa Persson <asapersson@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27684}
diff --git a/video/video_stream_decoder.cc b/video/video_stream_decoder.cc
index 3fdb905..0c4eeeb 100644
--- a/video/video_stream_decoder.cc
+++ b/video/video_stream_decoder.cc
@@ -35,7 +35,6 @@
   // callbacks.
 
   // Unset all the callback pointers that we set in the ctor.
-  video_receiver_->RegisterPacketRequestCallback(nullptr);
   video_receiver_->RegisterReceiveCallback(nullptr);
 }