Default `@Query(sort)` not applied for repository queries using keyset pagination

Using a query such as

```java
@Query(value = "{country:  'USA'}", sort = "{lastName:  -1, firstName: -1}")
Window<Person> findBy(Limit limit, ScrollPosition scrollPosition);
```

does not apply the default sort for keyset pagination because the decorated query proxy doesn't handle the `isSorted` method used by `ScrollUtils`.