Revert "Reland "Turn on WebRTC-TaskQueuePacer by defualt.""

This reverts commit 15a2159a350f57fb02a34b95e48236174fe4ca7f.

Reason for revert: Causing flakiness on video_engine_tests on Mac WebRTC builders. This is preventing WebRTC Rolls. The flakiness in occurred when b251145e38fdd08fe7320b0ddb3ca0f698473fa5 was merged as well. See https://ci.chromium.org/p/webrtc/builders/ci/Mac%20Asan and https://ci.chromium.org/p/webrtc/builders/ci/Mac64%20Release

Original change's description:
> Reland "Turn on WebRTC-TaskQueuePacer by defualt."
>
> This is a reland of b251145e38fdd08fe7320b0ddb3ca0f698473fa5
> Downstream test has been fixed.
>
> Original change's description:
> > Turn on WebRTC-TaskQueuePacer by defualt.
> >
> > Bug: webrtc:10809
> > Change-Id: If58ae3d9debc69ee68e6aeb6cecf010e60f6426f
> > Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/233580
> > Reviewed-by: Christoffer Rodbro <crodbro@webrtc.org>
> > Commit-Queue: Erik Språng <sprang@webrtc.org>
> > Cr-Commit-Position: refs/heads/main@{#35145}
>
> Bug: webrtc:10809
> Change-Id: Iac960e9edc9a25a958af0b51adab830ad9430edb
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/235209
> Reviewed-by: Sebastian Jansson <srte@webrtc.org>
> Commit-Queue: Erik Språng <sprang@webrtc.org>
> Cr-Commit-Position: refs/heads/main@{#35217}

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: webrtc:10809
Change-Id: Iadaefc05700490e20dbdc29f32f81e373e344683
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/235379
Reviewed-by: Evan Shrubsole <eshr@webrtc.org>
Reviewed-by: Andrey Logvin <landrey@webrtc.org>
Reviewed-by: Stefan Holmer <stefan@webrtc.org>
Commit-Queue: Evan Shrubsole <eshr@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35229}
diff --git a/call/rtp_transport_controller_send.cc b/call/rtp_transport_controller_send.cc
index 9d27b33..f7b6b11 100644
--- a/call/rtp_transport_controller_send.cc
+++ b/call/rtp_transport_controller_send.cc
@@ -89,7 +89,7 @@
       bitrate_configurator_(bitrate_config),
       pacer_started_(false),
       process_thread_(std::move(process_thread)),
-      use_task_queue_pacer_(!IsDisabled(trials, "WebRTC-TaskQueuePacer")),
+      use_task_queue_pacer_(IsEnabled(trials, "WebRTC-TaskQueuePacer")),
       process_thread_pacer_(use_task_queue_pacer_
                                 ? nullptr
                                 : new PacedSender(clock,