Allowing buffering a LNTF (loss notification) feedback message in RTCPSender

Loss notifications may either be sent immediately, or wait until another
RTCP feedback message is sent.

Bug: webrtc:10336
Change-Id: I40601d9fa1dec6c17b2ce905cb0c8cd2dcff7893
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/139242
Commit-Queue: Elad Alon <eladalon@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28142}

modules/include/module_common_types.h

@@ -100,7 +100,8 @@ class LossNotificationSender {
 
   virtual void SendLossNotification(uint16_t last_decoded_seq_num,
                                     uint16_t last_received_seq_num,
-                                    bool decodability_flag) = 0;
+                                    bool decodability_flag,
+                                    bool buffering_allowed) = 0;
 };
 
 }  // namespace webrtc