Remove unnecessary audio references in PeerConnectionFactory

sdk/objc/Framework/Classes/PeerConnection/RTCPeerConnectionFactory.mm

Index: sdk/objc/Framework/Classes/PeerConnection/RTCPeerConnectionFactory.mm
diff --git a/sdk/objc/Framework/Classes/PeerConnection/RTCPeerConnectionFactory.mm b/sdk/objc/Framework/Classes/PeerConnection/RTCPeerConnectionFactory.mm
index a42d76044f9f1de289ab0513a866f1385bb5ddfe..9694108b6e68c4a1192c4a8653ab475cb017f812 100644
--- a/sdk/objc/Framework/Classes/PeerConnection/RTCPeerConnectionFactory.mm
+++ b/sdk/objc/Framework/Classes/PeerConnection/RTCPeerConnectionFactory.mm
@@ -110,12 +110,8 @@
         _networkThread.get(),
         _workerThread.get(),
         _signalingThread.get(),
-        nullptr,  // default_adm
-        nullptr,  // audio_encoder_factory
-        nullptr,  // audio_decoder_factory
         nullptr,  // video_encoder_factory
         nullptr,  // video_decoder_factory
-        nullptr,  // audio_mixer
         std::unique_ptr<cricket::MediaEngineInterface>(),
         std::unique_ptr<webrtc::CallFactoryInterface>(),
         std::unique_ptr<webrtc::RtcEventLogFactoryInterface>());