The work area is really the space that is available to application
windows. Applying it to the overview is therefore questionable,
in particular given that
- X11 clients that affect struts aren't shown
- elements added by extensions have other means
to affect the overview layout
Not applying the work area to the overview also makes ignoring
actors' visibility for struts acceptable again: Assuming that
strut actors are only hidden when the monitor is in fullscreen,
freezing the work area instead of updating it for windows that
are fully obscured by a fullscreen windows makes perfect sense.
This reverts commits 81a1e294f8bd161 and 2b074882f44c32862e3.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2223>