feat: sort conversation on priority (#6943)

* feat: update seed script to include prioritt

* feat: add sort_handler for conversations

* test: sort on priority order

---------

Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

app/models/concerns/sort_handler.rb

@@ -21,5 +21,13 @@ module SortHandler
         'grouped_conversations.message_type', 'grouped_conversations.created_at ASC'
       )
     end
+
+    def self.sort_on_priority
+      order(
+        Arel::Nodes::SqlLiteral.new(
+          sanitize_sql_for_order('CASE WHEN priority IS NULL THEN 0 ELSE priority END DESC, last_activity_at DESC')
+        )
+      )
+    end
   end
 end