Add environment_construction poison

This poison guards against accidental use of EnvironmentFactory and thus ensures low level WebRTC class would use utilities from propagated environment instead of accidentally using a default implementation.

This poison extends and thus replaces default task queue poison.

Bug: webrtc:15656
Change-Id: I577bef8af08b9c7dd649ad5a2284eb236e6f4a8f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/328380
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#41247}
diff --git a/api/BUILD.gn b/api/BUILD.gn
index e57092e..c187a7d 100644
--- a/api/BUILD.gn
+++ b/api/BUILD.gn
@@ -54,7 +54,7 @@
   visibility = [ "*" ]
   allow_poison = [
     "audio_codecs",
-    "default_task_queue",
+    "environment_construction",
     "software_video_codecs",
   ]
   sources = [
@@ -77,7 +77,7 @@
 if (!build_with_chromium) {
   rtc_library("create_peerconnection_factory") {
     visibility = [ "*" ]
-    allow_poison = [ "default_task_queue" ]
+    allow_poison = [ "environment_construction" ]
     sources = [
       "create_peerconnection_factory.cc",
       "create_peerconnection_factory.h",