[website] Fix out of date discount value

This was spot by Greg, it's not consistent with https://support.mui.com/hc/en-us/articles/6930257969692-How-can-I-renew-my-MUI-X-licenses-.

docs/src/components/pricing/PricingWhatToExpect.tsx

@@ -83,7 +83,7 @@ export default function PricingWhatToExpect() {
             when you renew:
             <ul>
               <li>before the support expires: 50% discount</li>
-              <li>up to 60 days after the support has expired: 25% discount</li>
+              <li>up to 60 days after the support has expired: 35% discount</li>
               <li>more than 60 days after the support has expired: 15% discount</li>
             </ul>
           </Typography>