Expose defer_send_in_response_to_packets_ in QuicConnection to its subclasses.

No behavioral change.

PiperOrigin-RevId: 469791677
diff --git a/quiche/quic/core/quic_connection.h b/quiche/quic/core/quic_connection.h
index 5daf2bf..a38a7b9 100644
--- a/quiche/quic/core/quic_connection.h
+++ b/quiche/quic/core/quic_connection.h
@@ -1329,6 +1329,10 @@
     validate_client_addresses_ = value;
   }
 
+  bool defer_send_in_response_to_packets() const {
+    return defer_send_in_response_to_packets_;
+  }
+
  private:
   friend class test::QuicConnectionPeer;