Turn off light dismiss for non-toplevel menus.
Turn off light dismiss for non-toplevel menus.

#5295 enabled the light dismiss overlay for popups, which in turn broke submenu interactions (#5475). The fix seems to be simple: turn off light dismiss for non-toplevel menus. These menus will be in popups so this means their behavior will be reverted to that of before #5295.

Fixes #5475

SuperJMN/Avalonia,wieslawsoltes/Perspex,AvaloniaUI/Avalonia,Perspex/Perspex,AvaloniaUI/Avalonia,jkoritzinsky/Avalonia,SuperJMN/Avalonia,Perspex/Perspex,SuperJMN/Avalonia,wieslawsoltes/Perspex,AvaloniaUI/Avalonia,AvaloniaUI/Avalonia,jkoritzinsky/Avalonia,wieslawsoltes/Perspex,wieslawsoltes/Perspex,wieslawsoltes/Perspex,jkoritzinsky/Avalonia,SuperJMN/Avalonia,jkoritzinsky/Avalonia,SuperJMN/Avalonia,jkoritzinsky/Avalonia,jkoritzinsky/Perspex,SuperJMN/Avalonia,jkoritzinsky/Avalonia,AvaloniaUI/Avalonia,grokys/Perspex,wieslawsoltes/Perspex,wieslawsoltes/Perspex,grokys/Perspex,SuperJMN/Avalonia,jkoritzinsky/Avalonia,AvaloniaUI/Avalonia,AvaloniaUI/Avalonia