This remove use of MaybeWorkerThread from TaskQueuePacedSender. Instead,
the TaskQueue used when creating the TaskQueuePacedSender is used for
pacing. That is, the "worker thread".
Bug: webrtc:14502
Change-Id: I504f8e634653af6493e609db6e42b07d488fd699
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/300820
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Per Kjellander <perkj@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#39813}