build: fix clang compilation

missing header <functional>, change introduced in
989e9bdb

Issue: #78983
Change-Id: I0f8e3a57d13d85e982a9fcd8a38e57b9f19afc8a

src/ice_socket.h

@@ -30,6 +30,7 @@
 #define ICE_SOCKET_H
 
 #include <memory>
+#include <functional>
 
 namespace ring {