Remove unused field trial kill-switch WebRTC-LazyPacerStart.

Bug: webrtc:10809
Change-Id: I8f7e7b7c774aa038ac56dcdf447df9e84679b6ef
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/268143
Auto-Submit: Erik Språng <sprang@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#37479}
diff --git a/call/rtp_transport_controller_send.cc b/call/rtp_transport_controller_send.cc
index 704b9d5..fd9597d 100644
--- a/call/rtp_transport_controller_send.cc
+++ b/call/rtp_transport_controller_send.cc
@@ -131,10 +131,6 @@
 
   pacer_.SetPacingRates(DataRate::BitsPerSec(bitrate_config.start_bitrate_bps),
                         DataRate::Zero());
-
-  if (absl::StartsWith(trials.Lookup("WebRTC-LazyPacerStart"), "Disabled")) {
-    EnsureStarted();
-  }
 }
 
 RtpTransportControllerSend::~RtpTransportControllerSend() {