This is to make it generally more in line with the stylesheet as well
as to resolve the blue and white bleeding together in dark mode.
It's also consistent with switches in recent mockups.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3077>
- increase the looking glass outer radii
- adjust the colours to be less dark
- fix oversized notification close icon
- fix separators and reduce padding in popovers
- fix colour mismatch in switch assets
- fix color of no-notifications asset
- rename assets to be consistent with dark-as-default scheme
- update checkbox assets
- fix calendar today border
- reduce icon size of placeholder notifications icon
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2111>
