fix url preview spacing for very narrow viewports

on wide viewports, the url preview only leaves space for a thumbnail
when such thumbnail exists.

on small phones, or in busy deck views, it always left that space

this was not very evident for simple previews (which are pretty much a
title line, a favicon, and the site name), but it became very obvious
with the note embedding in 2024.11

this patch makes the thumbnail space conditional on the existence of
the thumbnail, for narrow viewports as well (I pretty much copied the
bit of CSS from the non-narrow media query sections)

0 files changed, 0 insertions, 0 deletions