Setting spring.reactor.context-propagation has no effect when lazy initialization is enabled

[nosan]

See #45846

[nosan]

I was initially thinking of the following approach:

@AutoConfiguration
@ConditionalOnClass(Hooks.class)
@ConditionalOnProperty(name = "spring.reactor.context-propagation", havingValue = "auto")
@EnableConfigurationProperties(ReactorProperties.class)
public class ReactorAutoConfiguration {

	ReactorAutoConfiguration() {
		Hooks.enableAutomaticContextPropagation();
	}

	@Bean
	static LazyInitializationExcludeFilter reactorLazyInitializationExcludeFilter() {
		return LazyInitializationExcludeFilter.forBeanTypes(ReactorAutoConfiguration.class);
	}

}

However, ReactorProperties will stop being registered, which makes this approach somewhat risky to merge.

As a good alternative, maybe something like this:

@AutoConfiguration
@ConditionalOnClass(Hooks.class)
@EnableConfigurationProperties(ReactorProperties.class)
public class ReactorAutoConfiguration {

	@Configuration(proxyBeanMethods = false)
	@ConditionalOnProperty(name = "spring.reactor.context-propagation", havingValue = "auto")
	static class ReactorContextPropagationConfiguration {

		ReactorContextPropagationConfiguration() {
			Hooks.enableAutomaticContextPropagation();
		}

		@Bean
		static LazyInitializationExcludeFilter reactorContextPropagationLazyInitExcludeFilter() {
			return LazyInitializationExcludeFilter.forBeanTypes(ReactorContextPropagationConfiguration.class);
		}

	}

}