Move code for setting field trials from NetEqTestFactory to the main function in neteq_rtpplay.

It is problematic to set field trials more than once, so to avoid running into problems, this functionality has been placed in the main function of neteq_rtpplay.

Bug: webrtc:9667
Change-Id: Ib9b9990f30a1715b50889dbfc4d74787bcbe5dae
Reviewed-on: https://webrtc-review.googlesource.com/98541
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Minyue Li <minyue@webrtc.org>
Commit-Queue: Ivo Creusen <ivoc@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24673}
diff --git a/api/BUILD.gn b/api/BUILD.gn
index c5c5713..a267894 100644
--- a/api/BUILD.gn
+++ b/api/BUILD.gn
@@ -344,6 +344,8 @@
       deps = [
         ":neteq_simulator_api",
         "../modules/audio_coding:neteq_test_factory",
+        "../rtc_base:checks",
+        "../rtc_base:rtc_base_approved",
         "//third_party/abseil-cpp/absl/memory",
       ]
     }