feat(webpage.rb): create buy_box_widget_data method

Author: MKwenhua

lib/cortex/snippets/webpage.rb

@@ -74,11 +74,15 @@ def accordion_group_widget_data
       def accordion_group_widget_data_for(section_name)
         accordion_group_widget_data&.[](section_name) || []
       end
-        
+
       def charts_widget_data
         JSON.parse(@webpage[:charts_widget_json] || 'null', quirks_mode: true)
       end
 
+      def buy_box_widget_data
+        JSON.parse(@webpage[:buy_box_widget_json] || 'null', quirks_mode: true)
+      end
+
       def charts_widget_data_for(section_name)
         charts_widget_data&.[](section_name) || {}
       end