Base class's 'Qt5FilePicker::setDescription'
does the same, namely nothing.

Change-Id: Ie89a1e1edaf20c49a1b16f43000a4a054b21f3b2
Reviewed-on: https://gerrit.libreoffice.org/68051
Tested-by: Jenkins
Reviewed-by: Katarina Behrens <Katarina.Behrens@cib.de>
(cherry picked from commit 3035db41)
Reviewed-on: https://gerrit.libreoffice.org/72648