Replace legacy getStats with standard getStats in the iOS example

Bug: webrtc:12688
Change-Id: I039cdae7647738d5f17b229c1137b72bf4aa7be0
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/219580
Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
Commit-Queue: Kári Helgason <kthelgason@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34063}
diff --git a/examples/objc/AppRTCMobile/ARDAppClient.h b/examples/objc/AppRTCMobile/ARDAppClient.h
index 1fed247..8e124ed 100644
--- a/examples/objc/AppRTCMobile/ARDAppClient.h
+++ b/examples/objc/AppRTCMobile/ARDAppClient.h
@@ -48,7 +48,7 @@
 
 - (void)appClient:(ARDAppClient *)client didError:(NSError *)error;
 
-- (void)appClient:(ARDAppClient *)client didGetStats:(NSArray *)stats;
+- (void)appClient:(ARDAppClient *)client didGetStats:(RTC_OBJC_TYPE(RTCStatisticsReport) *)stats;
 
 @optional
 - (void)appClient:(ARDAppClient *)client