Bug 35298: Remove focus handler from dateaccessioned plugin.

Bug 35298: Remove focus handler from dateaccessioned plugin.

Test plan:
Verify that setting focus to date acquired field in items editor
fills date of today when field is empty but does not replace existing
date.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit 0583deac95b35f1ad96493262e922d7ac3eef102)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>