Delete telephone-event handling from RTPReceiverAudio.

Bug: webrtc:7135
Change-Id: Ic8b96f44ba25ff9265570dd43d3c76ed0177abfb
Reviewed-on: https://webrtc-review.googlesource.com/91125
Reviewed-by: Oskar Sundbom <ossu@webrtc.org>
Reviewed-by: Åsa Persson <asapersson@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24172}

modules/rtp_rtcp/test/testAPI/test_api_audio.cc

@@ -57,7 +57,8 @@ void VerifyDtmf(const uint8_t* payloadData,
   EXPECT_TRUE(event < 16u || event == 32u);
   EXPECT_FALSE(reserved);
   EXPECT_EQ(volume, 10u);
-  EXPECT_LE(duration, 6560u);
+  // Long duration for answer tone events only
+  EXPECT_TRUE(duration <= 1280 || event == 32u);
 }
 
 class VerifyingAudioReceiver : public RtpData {