Use KNS3::QtQuickDialogWrapper instead of DownloadDialog.
In testing it seems refreshView() right after the kvtml files are installed is too soon to find them, will look into delaying that until later or periodically refreshing.
@leinir do I need to add some #if KNEWSTUFF_VERSION like kwordquiz has? or are most distros these days shipping at least the version of kns3 that added the QtQuickDialogWrapper ?