Disable more @Bean method proxying

Previously, due to a quirk in Spring Framework, it was necessary to use bean method
proxying in @Configuration classes that define one or more FactoryBeans. This quirk has
now been addressed so this commit disables bean method proxying where it is now no longer
needed.

Closes gh-16533

spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/web/client/TestRestTemplateContextCustomizerWithFactoryBeanTests.java

@@ -49,7 +49,7 @@ public class TestRestTemplateContextCustomizerWithFactoryBeanTests {
 		assertThat(this.restTemplate).isNotNull();
 	}
 
-	@Configuration
+	@Configuration(proxyBeanMethods = false)
 	@ComponentScan("org.springframework.boot.test.web.client.scan")
 	static class TestClassWithFactoryBean {