Bug 37411: Fixed exporting to CSV file

Bug 37411: Fixed exporting to CSV file

To test:
1. Acquistions -> Budgets -> Funds -> Planning, select any option
2. In the toolbar see Export, and click Submit and see a 500 error
3. Apply patch, restart_all
4. Repeat steps 1-2
5. Notice the 500 error is gone and the CSV is exported properly

Signed-off-by: Roman Dolny <roman.dolny@jezuici.pl>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit 94890a1e55735504b2f405c4b82793e3a2e44fc3)
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
(cherry picked from commit 3c8539bc6b4952922fe80c6e6714efb85b9ed9f1)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>