This was causing some bogus failures in Qt Quick autotests.
Existing APIs like QQuickWindow::mouseGrabberItem() are not really
compatible with the idea of a mouse-less system; but perhaps we can
revisit this later.
Task-number: QTBUG-85114
Change-Id: Id1c2e5894e5cf13a79998aaea28d5f42fad920cf
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>