So far we have only accepted QQmlListReference. However, we can also
pass a QQmlListProperty around as value.
Pick-to: 6.2 6.3 6.4
Fixes: QTBUG-105137
Change-Id: I7d4cd3048b62594298f91013c4cda5ec864a28df
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Andrei Golubev <andrei.golubev@qt.io>
Ulf Hermann