Ref T730, register metatype so struct can be used with signals

Remark: Unregistered it only works for direct connections

src/blackcore/afv/audio/receiversampleprovider.h

@@ -17,6 +17,7 @@
 
 #include "blackmisc/aviation/callsignset.h"
 #include "blackmisc/audio/audiosettings.h"
+
 #include <QtGlobal>
 
 namespace BlackCore
@@ -100,4 +101,6 @@ namespace BlackCore
     } // ns
 } // ns
 
+Q_DECLARE_METATYPE(BlackCore::Afv::Audio::TransceiverReceivingCallsignsChangedArgs)
+
 #endif // guard