Finally remove non-native menu bar

Change-Id: I4758bc5afa9f9eaced7763b9923250f27df14259
Reviewed-on: https://gerrit.libreoffice.org/58834
Tested-by: Jenkins
Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>

vcl/qt5/Qt5Menu.cxx

@@ -27,7 +27,7 @@ Qt5Menu::Qt5Menu(bool bMenuBar)
 
 Qt5Menu::~Qt5Menu() { maItems.clear(); }
 
-bool Qt5Menu::VisibleMenuBar() { return false; }
+bool Qt5Menu::VisibleMenuBar() { return true; }
 
 void Qt5Menu::InsertItem(SalMenuItem* pSalMenuItem, unsigned nPos)
 {