QUIC/HTTP3: reset idle timeout on ping

Summary:
Adds a transport callback for ping received.
Uses the callback in the HTTP3 session to reset the timeout

Reviewed By: mjoras

Differential Revision: D33101180

fbshipit-source-id: d6fcecd22cbd5c311674dd9421c0c54eb04728a0

quic/server/state/ServerStateMachine.cpp

@@ -1149,6 +1149,7 @@ void onServerReadDataFromOpen(
           // Ping isn't retransmittable data. But we would like to ack them
           // early.
           pktHasRetransmittableData = true;
+          conn.pendingEvents.notifyPingReceived = true;
           break;
         case QuicFrame::Type::PaddingFrame:
           break;