AnimatedImage does not seem to respect the asynchronous property.

AnimatedImage does not seem to respect the asynchronous property that it inherits from Image. 

This seems to be where QQuickImageBase is reacting to asynchronous qml property on the C++ side:  https://github.com/qt/qtdeclarative/blob/61199f3309a34f8f0a5d16add11e05537272bad0/src/quick/items/qquickimagebase.cpp#L281

And this is where QQuickAnimatedImage seems to be ignoring the asynchronous state set from qml: 

https://github.com/qt/qtdeclarative/blob/61199f3309a34f8f0a5d16add11e05537272bad0/src/quick/items/qquickanimatedimage.cpp#L281

Attached project is a minimum reproduction of the issue.

Its contains four image items, two are AnimatedImage items, and two Image items.

One of each of the items are set to load asynchronously. When all four images are set to load identical copies of a large static image file (see attached example image) only the Image item set to load asynchronously does not block the Spinner. The AnimatedImage set to load asynchronously still blocks the ui.