Freeze configuration before invoking MBDPP instances

This commit updates refresh for AOT processing so that the configuration
is frozen before invoking MergedBeanDefinitionPostProcessor instances.
This makes sure that post-processed MergedBeanDefinitions are kept in
cache and not lost if a component attempts to clear the metadata cache.

Closes gh-28941

spring-context/src/main/java/org/springframework/context/support/GenericApplicationContext.java

@@ -406,6 +406,7 @@ public class GenericApplicationContext extends AbstractApplicationContext implem
 		prepareBeanFactory(this.beanFactory);
 		postProcessBeanFactory(this.beanFactory);
 		invokeBeanFactoryPostProcessors(this.beanFactory);
+		this.beanFactory.freezeConfiguration();
 		PostProcessorRegistrationDelegate.invokeMergedBeanDefinitionPostProcessors(this.beanFactory);
 	}