Right now the spacing between icon and title works using a little trick
that doesn't really seem intended: The title is offset by
(icon-height * ICON_OVERLAP), when the icon is actually overlapping the
preview by ICON_OVERLAP, and *overflowing* the preview by
(1 - ICON_OVERLAP).
So correct that and offset the title by
(icon-height * (1 - ICON_OVERLAP)), and since now there's no spacing
anymore, add a proper ICON_TITLE_SPACING to that offset.
Also add the new ICON_TITLE_SPACING to the overlapHeight, where the
spacing was ignored so far.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1692>
3795ccbcf3