Add missing include to functional for chef (project-chip#31404)

Author: andy31415

examples/chef/common/chef-fan-control-manager.cpp

@@ -26,6 +26,8 @@
 #include <lib/support/CodeUtils.h>
 #include <lib/support/logging/CHIPLogging.h>
 
+#include <functional>
+
 using namespace chip;
 using namespace chip::app;
 using namespace chip::app::Clusters;