This allow exernal applications to control how many packets can be sent relative current BWE.
This is a partial revert of https://webrtc-review.googlesource.com/c/src/+/311102
Bug: chromium:1354491
Change-Id: Ia236aaacc468ddac12341efa555041bb2dfdde62
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/330580
Commit-Queue: Per Kjellander <perkj@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#41343}