feat: Conversation update API for sla_policy_id (#8973)

- Add an endpoint for updating conversation attributes (priority / sla_policy_id )
- Swagger spec
- minor chores around the conversation API/spec

Fixes: https://linear.app/chatwoot/issue/CW-2100/feat-backend-api-to-update-the-sla-of-a-conversation

enterprise/app/services/enterprise/action_service.rb

@@ -8,16 +8,5 @@ module Enterprise::ActionService
 
     Rails.logger.info "SLA:: Adding SLA #{sla_policy.id} to conversation: #{@conversation.id}"
     @conversation.update!(sla_policy_id: sla_policy.id)
-    create_applied_sla(sla_policy)
-  end
-
-  def create_applied_sla(sla_policy)
-    Rails.logger.info "SLA:: Creating Applied SLA for conversation: #{@conversation.id}"
-    AppliedSla.create!(
-      account_id: @conversation.account_id,
-      sla_policy_id: sla_policy.id,
-      conversation_id: @conversation.id,
-      sla_status: 'active'
-    )
   end
 end