Set it to nullptr on clear, and deal with possibly null bindingStatus.
Task-number: QTBUG-101177
Task-number: QTBUG-102403
Pick-to: 6.4
Change-Id: I66cb4d505a4f7b377dc90b45ac13834fca19d399
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>