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>

cataloguing/value_builder/dateaccessioned.pl

@@ -39,10 +39,6 @@ my $builder = sub {
     });
 });
 
-function Focus$function_name(event) {
-    set_to_today(event.data.id);
-}
-
 function Click$function_name(event) {
     set_to_today(event.data.id, 1);
     return false;