qt: fix for broken key navigation on offscreen window re-activation (x11)
- QQuickWindow should not clear focus when it loses focus (QTBUG-125309).
- Qt 6.7 is able to re-focus the previously focused item, when the window is re-activated.
- Qt 6.2 does not set the focus item when the window is re-activated. This causes issues with key event delivery, and therefore key navigation.