Remove unused critical section includes.

Bug: webrtc:11567
Change-Id: Ic5e43c51ce06c0619adc265d12ad4bef73a9df76
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/179521
Reviewed-by: Tommi <tommi@webrtc.org>
Commit-Queue: Markus Handell <handellm@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31745}

api/BUILD.gn

@@ -579,10 +579,7 @@ rtc_source_set("bitrate_allocation") {
 rtc_source_set("simulated_network_api") {
   visibility = [ "*" ]
   sources = [ "test/simulated_network.h" ]
-  deps = [
-    "../rtc_base",
-    "../rtc_base:criticalsection",
-  ]
+  deps = [ "../rtc_base" ]
   absl_deps = [ "//third_party/abseil-cpp/absl/types:optional" ]
 }