If a control is contained in a wxStaticBoxSizer or its child sizer,
wxStaticBoxSizer::GetStaticBox() should be used as the control's parent.
However, widgets and dialogs samples did not do that, which resulted in
flooding the message log in widgets sample with warnings about this; in
dialogs sample the warnings were shown in the debug output.
Fix this by always using the static box as the control's parent when the
control is contained (directly or indirectly) in a wxStaticBoxSizer.
Closes#23967.
a69fabecb1