chore: Limit the number of articles retrieved by widget (#11095)

The UI displays only six articles, and this update introduces a per_page
parameter to control the number of articles returned per API call. The
value is capped between 1 and 100, with a default fallback if a lower
number is set.

This change is necessary due to high website traffic, where excessive
payloads are returned without adding value.

**Changes:** 
- Add index to status, account_id, portal_id, views.
- Add per_page param in the API.
- Update the code in the frontend to fetch only 6

db/migrate/20250315202035_add_index_to_articles.rb

@@ -0,0 +1,8 @@
+class AddIndexToArticles < ActiveRecord::Migration[7.0]
+  def change
+    add_index :articles, :status unless index_exists?(:articles, :status)
+    add_index :articles, :views unless index_exists?(:articles, :views)
+    add_index :articles, :portal_id unless index_exists?(:articles, :portal_id)
+    add_index :articles, :account_id unless index_exists?(:articles, :account_id)
+  end
+end