This patch does 2 things.

1. Check for the iconSource as defined in Action.qml

2. Mitigate the misuse of QUrl in desktopicon.cpp

Note that this isn't 100% correct. Imageprovider strings are not really URL, they are URI, it can be anything and include URI arguments. I think the proper solution would be to check exactly what QML does when ocnversion image:// into identifier and do exactly that. Right now a string that works in Image{} and was valid per the image provider doc was modified by QUrl into something else.

Manual testing