WindowServer: Recalculate window rect when toggling menubar

This is important when the window is maximized or tiled (which
recalculate_rect() will both check), as we otherwise create a gap above
the window frame (when hiding the menubar) or push the frame off the
screen (when showing the menubar).

Userland/Services/WindowServer/Window.cpp

@@ -700,6 +700,7 @@ void Window::ensure_window_menu()
                 item.set_checked(!item.is_checked());
                 m_should_show_menubar = item.is_checked();
                 frame().invalidate();
+                recalculate_rect();
                 Compositor::the().invalidate_occlusions();
                 Compositor::the().invalidate_screen();
                 break;