Bug 28538: Insert formatted date if valid

Bug 28538: Insert formatted date if valid

This patch restores the setting of the date from bug 27937 and adds a parsing of the date to
ensure the correct format

To test:
1 - Follow test plan from bug 27937 - it fails
2 - Follow test plan from bug 28351 - it succeeds
3 - Apply patch
4 - Repeat 1-2
5 - both plans pass now

Signed-off-by: Andrew Fuerste-Henry <andrew@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>