Fix variable targetClassToUse not used

Closes spring-projectsgh-15567

core/src/main/java/org/springframework/security/authorization/method/PostAuthorizeExpressionAttributeRegistry.java

@@ -78,7 +78,7 @@ private MethodAuthorizationDeniedHandler resolveHandler(Method method, Class<?>
 
 	private PostAuthorize findPostAuthorizeAnnotation(Method method, Class<?> targetClass) {
 		Class<?> targetClassToUse = targetClass(method, targetClass);
-		return this.postAuthorizeSynthesizer.synthesize(method, targetClass);
+		return this.postAuthorizeSynthesizer.synthesize(method, targetClassToUse);
 	}
 
 	/**