[#1891] Fix getReference issue with BE

ORM 6.5 doesn't create a proxy factory unless is needed.
When we upgraded we missed a small change to the flow because
we didn't have tests for it (`getReference` with Bytecode Enhancements
enabled).

Author: DavideD

hibernate-reactive-core/src/main/java/org/hibernate/reactive/event/impl/DefaultReactiveLoadEventListener.java

@@ -361,7 +361,7 @@ else if ( persister.getRepresentationStrategy().getProxyFactory() != null ) {
 			// we have a HibernateProxy factory, this case is more complicated
 			return loadWithProxyFactory( event, persister, keyToLoad );
 		}
-		else if ( !persister.hasSubclasses() ) {
+		else if ( persister.hasSubclasses() ) {
 			// the entity class has subclasses and there is no HibernateProxy factory
 			return load( event, persister, keyToLoad, options );
 		}