Accessibility status icon popup menu improvement.

Eight years ago a commit permitted toggling switches in the menu without closing it by using the space key, but in Gnome 3.36.6 this causes the menu to close on a click-event. Mouse-click events should behave as they do for the toggle switch in the Calendar popup menu. Space still allows toggling without closing the menu, enter/return toggles and then closes the menu, and mouse-clicks perform the same as the space-key. Removes a general annoyance and improves consistency across the Gnome shell.

Note that the calendar.js does not allow closing its resulting popup menu when enter/return key events are passed to the toggle switch 'dnd-switch.' I don't know how to fix that.