Exposing rtcp report interval setting in objc api

Bug: webrtc:8789
Change-Id: I75d8cac70de00b067cbbcbe7faa3d3ccb0318453
Reviewed-on: https://webrtc-review.googlesource.com/c/110846
Reviewed-by: Anders Carlsson <andersc@webrtc.org>
Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
Commit-Queue: Jiawei Ou <ouj@fb.com>
Cr-Commit-Position: refs/heads/master@{#25643}

sdk/objc/api/peerconnection/RTCConfiguration.h

@@ -201,6 +201,16 @@ RTC_OBJC_EXPORT
  */
 @property(nonatomic, nullable) RTCCryptoOptions *cryptoOptions;
 
+/**
+ * Time interval between audio RTCP reports.
+ */
+@property(nonatomic, assign) int rtcpAudioReportIntervalMs;
+
+/**
+ * Time interval between video RTCP reports.
+ */
+@property(nonatomic, assign) int rtcpVideoReportIntervalMs;
+
 - (instancetype)init;
 
 @end