Display the global menu bar if the last TLW is hidden in wxOSX

Hiding the last TLW should be enough to show the global menu bar, but this
only happened if it was closed and not just hidden.

Closes #16201.

include/wx/osx/menu.h

@@ -152,6 +152,7 @@ public:
     static void SetAutoWindowMenu( bool enable ) { s_macAutoWindowMenu = enable ; }
     static bool GetAutoWindowMenu() { return s_macAutoWindowMenu ; }
 
+    void MacUninstallMenuBar() ;
     void MacInstallMenuBar() ;
     static wxMenuBar* MacGetInstalledMenuBar() { return s_macInstalledMenuBar ; }
     static void MacSetCommonMenuBar(wxMenuBar* menubar) { s_macCommonMenuBar=menubar; }