Remove the usage of the field-trial WebRTC-Aec3DeactivateInitialStateResetKillSwitch

Bug: webrtc:42233815
Change-Id: I864c14e6090fb8a87f8c452601d6a3ce7836c6cd
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/465803
Commit-Queue: Per Åhgren <peah@webrtc.org>
Reviewed-by: Jesus de Vicente Pena <devicentepena@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#47531}

modules/audio_processing/aec3/aec_state.cc

diff --git a/modules/audio_processing/aec3/aec_state.cc b/modules/audio_processing/aec3/aec_state.cc
index 4c25a58..0ee49f0 100644
--- a/modules/audio_processing/aec3/aec_state.cc
+++ b/modules/audio_processing/aec3/aec_state.cc
@@ -38,12 +38,6 @@
 namespace webrtc {
 namespace {
 
-bool DeactivateInitialStateResetAtEchoPathChange(
-    const FieldTrialsView& field_trials) {
-  return field_trials.IsEnabled(
-      "WebRTC-Aec3DeactivateInitialStateResetKillSwitch");
-}
-
 bool SubtractorAnalyzerResetAtEchoPathChange(
     const FieldTrialsView& field_trials) {
   return !field_trials.IsEnabled(
@@ -127,8 +121,6 @@
     : data_dumper_(new ApmDataDumper(instance_count_.fetch_add(1) + 1)),
       config_(config),
       num_capture_channels_(num_capture_channels),
-      deactivate_initial_state_reset_at_echo_path_change_(
-          DeactivateInitialStateResetAtEchoPathChange(env.field_trials())),
       subtractor_analyzer_reset_at_echo_path_change_(
           SubtractorAnalyzerResetAtEchoPathChange(env.field_trials())),
       initial_state_(config_),
@@ -155,9 +147,7 @@
     capture_signal_saturation_ = false;
     strong_not_saturated_render_blocks_ = 0;
     blocks_with_active_render_ = 0;
-    if (!deactivate_initial_state_reset_at_echo_path_change_) {
-      initial_state_.Reset();
-    }
+    initial_state_.Reset();
     if (transparent_state_) {
       transparent_state_->Reset();
     }

modules/audio_processing/aec3/aec_state.h

diff --git a/modules/audio_processing/aec3/aec_state.h b/modules/audio_processing/aec3/aec_state.h
index 26bd2ee..17649bf 100644
--- a/modules/audio_processing/aec3/aec_state.h
+++ b/modules/audio_processing/aec3/aec_state.h
@@ -166,7 +166,6 @@
   std::unique_ptr<ApmDataDumper> data_dumper_;
   const EchoCanceller3Config config_;
   const size_t num_capture_channels_;
-  const bool deactivate_initial_state_reset_at_echo_path_change_;
   const bool subtractor_analyzer_reset_at_echo_path_change_;
 
   // Class for controlling the transition from the intial state, which in turn