Fix return type of hibernate-search substitution

Complementary to quarkusio#35847

extensions/hibernate-search-orm-elasticsearch/runtime/src/main/java/io/quarkus/hibernate/search/orm/elasticsearch/runtime/graal/Substitute_JandexBehavior.java

@@ -13,7 +13,7 @@
 final class Substitute_JandexBehavior {
 
     @Substitute
-    public static <T> T doWithJandex(JandexBehavior.JandexOperation operation) {
+    public static void doWithJandex(JandexBehavior.JandexOperation operation) {
         throw new IllegalStateException("Jandex should not be used at runtime.");
     }