QML: Make QtAudioEngine import available under 1.QT_MINOR_VERSION

Made the QtAudioEngine import always available under the latest Qt minor version
import QtAudioEngine 1.13
for 5.13

Task-number: QTBUG-74031
Change-Id: I14f602a5c59a6a6906aeeda8644e64dae36312e3
Reviewed-by: Kai Koehne <kai.koehne@qt.io>