driver: Set a non-trivial window title
When running in "existing user" mode (which isn't done upstream, but Debian and Ubuntu re-enable it because they don't have GNOME Tour), the window title is visible in Alt+[key above Tab] and the Overview. It defaults to "gnome-initial-setup", but looks better if we reuse the translated name from the .desktop file.
I think this avoids breaking string freeze because the .desktop file already marks Initial Setup
for translation, but I'm not very good at gettext.