feat: Conversation workflow backend changes (#13070)

Extracted the backend changes from
https://github.com/chatwoot/chatwoot/pull/13040

- Added the support for saving `conversation_required_attributes` in
account
- Delete `conversation_required_attributes` if custom attribute deleted.

Co-authored-by: Vinay Keerthi <11478411+stonecharioteer@users.noreply.github.com>

app/models/custom_attribute_definition.rb

@@ -45,6 +45,7 @@ class CustomAttributeDefinition < ApplicationRecord
   belongs_to :account
   after_update :update_widget_pre_chat_custom_fields
   after_destroy :sync_widget_pre_chat_custom_fields
+  after_destroy :cleanup_conversation_required_attributes
 
   private
 
@@ -56,6 +57,13 @@ class CustomAttributeDefinition < ApplicationRecord
     ::Inboxes::UpdateWidgetPreChatCustomFieldsJob.perform_later(account, self)
   end
 
+  def cleanup_conversation_required_attributes
+    return unless conversation_attribute? && account.conversation_required_attributes&.include?(attribute_key)
+
+    account.conversation_required_attributes = account.conversation_required_attributes - [attribute_key]
+    account.save!
+  end
+
   def attribute_must_not_conflict
     model_keys = attribute_model.to_sym == :conversation_attribute ? :conversation : :contact
     return unless attribute_key.in?(STANDARD_ATTRIBUTES[model_keys])