Calculate the total rental rate for animation film titles.
animation film refers to category.name = 'Animation'; total rental rate = sum(rental_rate)
SELECT SUM(T1.rental_rate) FROM film AS T1 INNER JOIN film_category AS T2 ON T1.film_id = T2.film_id INNER JOIN category AS T3 ON T2.category_id = T3.category_id WHERE T3.`name` = 'Animation'