BannerImage: Delay recalculating title size until after anchors have settled

The order of binding evaluation is not determined. This means that we can sometimes end up in a state where both left and right anchors are set. In that case, the item ends up being resized to full width first and then the other anchor is released, but the size is still wrong. This then means alignment is broken. To fix this, we need to tell QtQuick to recalculate the size once the anchors have settled.

The second commit adds a manual test for cards.