Fix GetColumnCount() not working for wxRadioBox in wxQt

Add missing SetMajorDim() call to wxRadioBox::Create().

Closes https://github.com/wxWidgets/wxWidgets/pull/1144

src/qt/radiobox.cpp

@@ -188,6 +188,7 @@ bool wxRadioBox::Create(wxWindow *parent,
 
     m_qtGroupBox->setLayout(horzLayout);
 
+    SetMajorDim(majorDim == 0 ? n : majorDim, style);
     return QtCreateControl( parent, id, pos, size, style, val, name );
 }