fix: require migration class in rake task before invoking

lib/tasks/migrate_max_assignment_limit.rake

@@ -6,6 +6,7 @@
 namespace :assignment do
   desc 'Migrate max_assignment_limit from inbox config to agent capacity policies'
   task migrate_max_limit: :environment do
+    require Rails.root.join('db/migrate/20260316000001_migrate_max_assignment_limit_to_policies')
     MigrateMaxAssignmentLimitToPolicies.new.up
   end
 end