QStyleSheetStyle::drawPrimitive(QStyle::PE_PanelLineEdit) crashes with widget==nullptr

Using QStyleSheetStyle::drawPrimitive to draw a QStyle::PE_PanelLineEdit with a nullptr optional widget (i.e. the method default argument for widget parameter) leads to a crash.

I have attached a simple example to demonstrate the crash - this runs fine in Qt 5.15.2, but crashes in Qt 6.2.4 and 6.3.0 (these are the versions I have easily available). The attached example does not attempt to do anything sensible, it is merely a demonstration of the crash; I discovered it in a much more reasonable scenario and have simplified it to make your debugging life easier.

I believe it's because of the change made in QTBUG-95631 to use containerWidget(widget) - there is no null pointer check there.