Zero values are not displayed in integer columns

Summary:
(for byte/short/int/big int)

BUG:395189

Test Plan: See https://bugs.kde.org/show_bug.cgi?id=395189#c1

Reviewers: piggz

Reviewed By: piggz

Subscribers: Kexi-Devel-list

Tags: #kexi

Differential Revision: https://phabricator.kde.org/D13451