Delete SetRtcpXrRrtrStatus, make it a construction-time setting

Bug: None
Change-Id: If2c42af6038c2ce1dc4289b949a0a3a279bae1b9
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/195337
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Åsa Persson <asapersson@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32754}

modules/rtp_rtcp/source/rtp_rtcp_impl.h

@@ -247,9 +247,6 @@ class ModuleRtpRtcpImpl : public RtpRtcp, public RTCPReceiver::ModuleRtpRtcp {
                                          const uint8_t* data,
                                          uint16_t length) override;
 
-  // (XR) Receiver reference time report.
-  void SetRtcpXrRrtrStatus(bool enable) override;
-
   // Video part.
   int32_t SendLossNotification(uint16_t last_decoded_seq_num,
                                uint16_t last_received_seq_num,