bug#41250: 28.0.50; Dired displays unconditionally ls-switches on modeline

[Eli Zaretskii]

> Date: Fri, 15 May 2020 11:55:46 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> Cc: 41250@debbugs.gnu.org, Juri Linkov <juri@linkov.net>
> 
> an integer - show first N chars of switches

I don't think this is a useful value: the user will rarely know how
much space is available on the mode line.  Also, truncating without
showing ellipsis or some other sign of truncation is IMO a sub-optimal
UI.

Thanks.