DataTargetVisitor should be package private to support AOT

`AuthorizeProxyDataConfiguration` exposes a `private` class as a bean:

```java
@Bean
@Role(BeanDefinition.ROLE_INFRASTRUCTURE)
DataTargetVisitor dataTargetVisitor() {
	return new DataTargetVisitor();
}
```

This needs to change to package-private so that the generated AOT class can construct the bean without reflection.