Move QAbstractItemModel QML workaround to declarativeplugin

This is necessary to fix a QML issue when running kdeconnet-app on non-Plasma desktops.

(cherry picked from commit af94100952)

declarativeplugin/kdeconnectdeclarativeplugin.cpp

@@ -122,6 +122,13 @@ void KdeConnectDeclarativePlugin::registerTypes(const char* uri)
             return new DaemonDbusInterface;
         }
     );
+
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 14, 0))
+    qmlRegisterAnonymousType<QAbstractItemModel>(uri, 1);
+#else
+    qmlRegisterType<QAbstractItemModel>();
+#endif
+
 }
 
 void KdeConnectDeclarativePlugin::initializeEngine(QQmlEngine* engine, const char* uri)

smsapp/main.cpp

@@ -64,7 +64,6 @@ int main(int argc, char *argv[])
 
     KDBusService service(KDBusService::Unique);
 
-    qmlRegisterType<QAbstractItemModel>();
     qmlRegisterType<OurSortFilterProxyModel>("org.kde.kdeconnect.sms", 1, 0, "QSortFilterProxyModel");
     qmlRegisterType<ConversationModel>("org.kde.kdeconnect.sms", 1, 0, "ConversationModel");
     qmlRegisterType<ConversationListModel>("org.kde.kdeconnect.sms", 1, 0, "ConversationListModel");