An RTP dump may or may not include the payload of the recorded RTP packets. When the payload is not present packets should still be created with their original packet length. Bug: webrtc:14801 Change-Id: Ice74cb5f7d370aaefac5f370445ffd3f2fc5924c Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/289920 Commit-Queue: Philip Eliasson <philipel@webrtc.org> Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org> Cr-Commit-Position: refs/heads/main@{#38979}