Resolves: fdo#73806 reduce the size-request of the expert config dialog

the optimal size was set to be 1024x800, reduce this down to
effectively the same size as the options dialog itself.

This dialog just isn't ever going to be right given the huge
length of the strings and the number of strings. We need
something more like a file picker dialog view here

Change-Id: I019e951601c3df769a609b8b439b535b6d5e254f
(cherry picked from commit 877aa0e1e879b057027029c1ceed07f90b00b0d3)
Reviewed-on: https://gerrit.libreoffice.org/10182
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
Tested-by: Markus Mohrhard <markus.mohrhard@googlemail.com>