The way it is currently calculated is broken for days with DST changes
or leap seconds and it is not needed anymore anyway. This will also make
the fix in the following commit simpler.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2023>
Here's a template string with '/' that escaped commit 94423151b2,
resulting in an xgettext warning when generating the .pot file.
Simply move it into the resource like the other interface descriptions
to make xgettext happy again.
https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/407