Removing unneeded dependency.

The //audio build target does not depend on the
builtin_audio_encoder_factory, this CL removes it from the dependency
list in order to avoid to propagate symbols that are not supposed to
be there.

Bug: webrtc:9528
Change-Id: Ib3868ee93f61057f61283faaa83e0633ebfdea90
Reviewed-on: https://webrtc-review.googlesource.com/89002
Reviewed-by: Yves Gerey <yvesg@webrtc.org>
Reviewed-by: Oskar Sundbom <ossu@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24019}
diff --git a/audio/BUILD.gn b/audio/BUILD.gn
index 22ceeb6..37793d3 100644
--- a/audio/BUILD.gn
+++ b/audio/BUILD.gn
@@ -54,7 +54,6 @@
     "../api/audio:audio_frame_api",
     "../api/audio:audio_mixer_api",
     "../api/audio_codecs:audio_codecs_api",
-    "../api/audio_codecs:builtin_audio_encoder_factory",
     "../call:bitrate_allocator",
     "../call:call_interfaces",
     "../call:rtp_interfaces",