core: don't hit an assert when printing status messages about units with...

core: don't hit an assert when printing status messages about units with overly long description strings

This essentially reverts one part of d054f0a4.

(We might also choose to use proper ellipsation here, but I wasn't sure the
memory allocation this requires wouöld be a good idea here...)

Fixes: #4534
(cherry picked from commit 07ecca0d)