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

app/views/api/v1/models/_account.json.jbuilder

@@ -1,6 +1,11 @@
 json.auto_resolve_duration resource.auto_resolve_duration
 json.created_at resource.created_at
-json.custom_attributes resource.custom_attributes
+if resource.custom_attributes.present?
+  json.custom_attributes do
+    json.plan_name resource.custom_attributes['plan_name']
+    json.subscribed_quantity resource.custom_attributes['subscribed_quantity']
+  end
+end
 json.custom_email_domain_enabled @account.custom_email_domain_enabled
 json.domain @account.domain
 json.features @account.enabled_features