Only register DynamicPropertySourceBeanInitializer if necessary

This commit makes sure to check first if
DynamicPropertySourceBeanInitializer has been registered before trying
to register it.

When running with AOT optimizations, the bean definition has been
contributed so there is no need to register it again when the context
customizer runs.

Closes gh-33272

Author: snicoll

Diff for: spring-test/src/main/java/org/springframework/test/context/support/DynamicPropertiesContextCustomizer.java

@@ -78,10 +78,12 @@ public void customizeContext(ConfigurableApplicationContext context, MergedConte
 				new DefaultDynamicPropertyRegistry(environment, this.methods.isEmpty());
 		beanFactory.registerSingleton(DYNAMIC_PROPERTY_REGISTRY_BEAN_NAME, dynamicPropertyRegistry);
 
-		BeanDefinition beanDefinition = new RootBeanDefinition(DynamicPropertySourceBeanInitializer.class);
-		beanDefinition.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
-		beanDefinitionRegistry.registerBeanDefinition(
-				DYNAMIC_PROPERTY_SOURCE_BEAN_INITIALIZER_BEAN_NAME, beanDefinition);
+		if (!beanDefinitionRegistry.containsBeanDefinition(DYNAMIC_PROPERTY_SOURCE_BEAN_INITIALIZER_BEAN_NAME)) {
+			BeanDefinition beanDefinition = new RootBeanDefinition(DynamicPropertySourceBeanInitializer.class);
+			beanDefinition.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
+			beanDefinitionRegistry.registerBeanDefinition(
+					DYNAMIC_PROPERTY_SOURCE_BEAN_INITIALIZER_BEAN_NAME, beanDefinition);
+		}
 
 		if (!this.methods.isEmpty()) {
 			MutablePropertySources propertySources = environment.getPropertySources();