core: slim down `common.hpp`

Change-Id: I875c35147edd2261fbaa24e809c170d5cd9b94d3
diff --git a/daemon/face/unicast-udp-transport.hpp b/daemon/face/unicast-udp-transport.hpp
index 4aa7233..fd6d645 100644
--- a/daemon/face/unicast-udp-transport.hpp
+++ b/daemon/face/unicast-udp-transport.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2023,  Regents of the University of California,
+ * Copyright (c) 2014-2024,  Regents of the University of California,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
  *                           University Pierre & Marie Curie, Sorbonne University,
@@ -28,6 +28,8 @@
 
 #include "datagram-transport.hpp"
 
+#include <ndn-cxx/util/scheduler.hpp>
+
 #include <boost/asio/ip/udp.hpp>
 
 namespace nfd::face {
@@ -57,7 +59,7 @@
 
 private:
   const time::nanoseconds m_idleTimeout;
-  scheduler::ScopedEventId m_closeIfIdleEvent;
+  ndn::scheduler::ScopedEventId m_closeIfIdleEvent;
 };
 
 } // namespace nfd::face