Fixes #37938 - Reject start-at dates in the past when a job is scheduled

Signed-off-by: Pablo Fernández Rodríguez <pafernan@redhat.com>

app/models/foreman_tasks/triggering.rb

@@ -127,5 +127,4 @@ def start_at_is_not_past
       errors.add(:start_at, _('is in the past')) if !start_at.nil? && Time.zone.parse(start_at_raw) < Time.zone.now
     end
   end
-end
-future
+end