message: [dbus] remove inclusion of code_utils.hpp in dbus api header
  common/code_utils.hpp includes macros like VerifyOrDie which are not
  protected by C++ namespace, so it will easily get conflicted with
  other definitions.
  We should not include common/code_utils.hpp in public headers.
diff: #include <dbus/dbus.h>
  -#include "common/code_utils.hpp"
  #include "common/types.hpp"
  #include "dbus/common/constants.hpp"
  #include "dbus/common/error.hpp"
  @@ -685,7 +684,7 @@ private:
  static void sScanPendingCallHandler(DBusPendingCall *aPending, void *aThreadApiDBus);
  void ScanPendingCallHandler(DBusPendingCall *aPending);
  - static void EmptyFree(void *aData) { OTBR_UNUSED_VARIABLE(aData); }
  + static void EmptyFree(void *) {}
  std::string mInterfaceName;
  