Add /donation/cancel route to fix 404 on cancelled PayPal donations

Redirects to the game dashboard instead of 404ing.

src/Website/Controller/HomeController.php

@@ -29,4 +29,10 @@ final class HomeController extends AbstractController
         return $this->render(
             'website/home/help_wanted.html.twig');
     }
+
+    #[Route(path: '/donation/cancel', name: 'website_donation_cancel')]
+    public function donationCancel(): Response
+    {
+        return $this->redirectToRoute('game_dashboard');
+    }
 }