Bug 27569: Fix ODS export - take empty string into account

Bug 27569: Fix ODS export - take empty string into account

If a cell contains an empty string it was not taken into account.

Test plan:
Same as CSV but with ODS

Signed-off-by: Ron Houk <rhouk@ottumwapubliclibrary.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
(cherry picked from commit 93bc3af5a9b72d5d15a76648e9b9cd7a963bd05f)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>
(cherry picked from commit 5dfc3942f6eb42f8201b8e4826c50fdc81fee3aa)

Signed-off-by: Andrew Fuerste-Henry <andrew@bywatersolutions.com>