refactor: Optimise article query in chat widget (#7919)

- optimise article query in chatwidget

app/views/public/api/v1/portals/articles/index.json.jbuilder

@@ -1,5 +1,6 @@
 json.payload do
-  json.array! @articles, partial: 'public/api/v1/models/article', formats: [:json], as: :article
+  json.array! @articles.includes([:category, :associated_articles, { author: { avatar_attachment: [:blob] } }]),
+              partial: 'public/api/v1/models/article', formats: [:json], as: :article
 end
 
 json.meta do