Add Duo Enterprise product interaction for seat assignment lead

What does this MR do and why?

Add Duo Enterprise product interaction for seat assignment lead

• we need to handle duo pro and duo enterprise for the iterable lead triggers on user assignment.
• implement a new bulk worker as it will be faster to see the impact AND the worker name could be improved.
• Fix a bug with the bulk worker where Set was being passed instead of an array.
• see Add product interaction value for duo enterpris... (#495116 - closed)

Changelog: other EE: true

MR acceptance checklist

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Related to #495116 (closed)

ee/app/models/gitlab_subscriptions/add_on_purchase.rb

@@ -52,6 +52,8 @@ class AddOnPurchase < ApplicationRecord
         .limit(limit)
     end
 
+    delegate :name, to: :add_on, prefix: true, allow_nil: true
+
     def self.find_by_namespace_and_add_on(namespace, add_on)
       find_by(namespace: namespace, add_on: add_on)
     end
@@ -110,10 +112,6 @@ def delete_ineligible_user_assignments_in_batches!(batch_size: 50)
       deleted_assignments_count
     end
 
-    def add_on_type
-      add_on.name.to_sym
-    end
-
     private
 
     def filter_ineligible_assigned_user_ids(assigned_user_ids)
@@ -128,7 +126,7 @@ def saas_eligible_user_ids
 
     def self_managed_eligible_users_relation
       @self_managed_eligible_users_relation ||= GitlabSubscriptions::SelfManaged::AddOnEligibleUsersFinder.new(
-        add_on_type: add_on_type
+        add_on_type: add_on_name.to_sym
       ).execute
     end