[Turbo] Fix checking "topics" option in Broadcaster

Mercure Broadcaster class was checking for the "topic" option, which is incorrect. This fixes that by checking for "topics" option instead.

Author: wooky

src/Turbo/src/Bridge/Mercure/Broadcaster.php

@@ -70,7 +70,7 @@ public function broadcast(object $entity, string $action, array $options): void
             throw new \InvalidArgumentException(sprintf('Cannot broadcast entity of class "%s" as option "rendered_action" is missing.', $entityClass));
         }
 
-        if (!isset($options['topic']) && !isset($options['id'])) {
+        if (!isset($options['topics']) && !isset($options['id'])) {
             throw new \InvalidArgumentException(sprintf('Cannot broadcast entity of class "%s": either option "topics" or "id" is missing, or the PropertyAccess component is not installed. Try running "composer require property-access".', $entityClass));
         }