feat: Allow SaaS users to manage subscription within the dashboard (#5059)

enterprise/app/models/enterprise/account.rb

@@ -1,13 +1,18 @@
 module Enterprise::Account
   def usage_limits
     {
-      agents: get_limits(:agents).to_i,
+      agents: agent_limits,
       inboxes: get_limits(:inboxes).to_i
     }
   end
 
   private
 
+  def agent_limits
+    subscribed_quantity = custom_attributes['subscribed_quantity']
+    subscribed_quantity || get_limits(:agents)
+  end
+
   def get_limits(limit_name)
     config_name = "ACCOUNT_#{limit_name.to_s.upcase}_LIMIT"
     self[:limits][limit_name.to_s] || GlobalConfig.get(config_name)[config_name] || ChatwootApp.max_limit