fdo#46037: remove unused comphelper/configurationhelper.hxx

Change-Id: I66f9d2912202ba1393d0c65189f8a945bca4fcaa
Reviewed-on: https://gerrit.libreoffice.org/10603
Tested-by: LibreOffice gerrit bot <gerrit@libreoffice.org>
Reviewed-by: Michael Stahl <mstahl@redhat.com>