chore: Fix link generation logic in help-center (#5470)

app/views/api/v1/accounts/articles/_article.json.jbuilder

@@ -10,6 +10,7 @@ json.category do
   json.id article.category_id
   json.name article.category.name
   json.slug article.category.slug
+  json.locale article.category.locale
 end
 
 if article.portal.present?