Inconsistent ReactiveOAuth2UserService in OAuth2LoginSpec

[blacelle]

Describe the bug
The way to configure a ReactiveOAuth2UserService<OAuth2UserRequest, OAuth2User> in OAuth2LoginSpec is inconsistent.

More specifically:

• OAuth2LoginReactiveAuthenticationManager constructor is called over getOauth2UserService() which search for a bean of type ReactiveOAuth2UserService, else fallback on DefaultReactiveOAuth2UserService
• OidcReactiveOAuth2UserService is instanciated by its default constructor, without relying on getOauth2UserService()

		private ReactiveAuthenticationManager createDefault() {
			[...]
			OAuth2LoginReactiveAuthenticationManager oauth2Manager = new OAuth2LoginReactiveAuthenticationManager(
					client, getOauth2UserService());

		private ReactiveOAuth2UserService<OidcUserRequest, OidcUser> getOidcUserService() {
			ResolvableType type = ResolvableType.forClassWithGenerics(ReactiveOAuth2UserService.class,
					OidcUserRequest.class, OidcUser.class);
			ReactiveOAuth2UserService<OidcUserRequest, OidcUser> bean = getBeanOrNull(type);
			if (bean != null) {
				return bean;
			}
			return new OidcReactiveOAuth2UserService();
		}

This leads to inconsistent ReactiveOAuth2UserService through the components created by OAuth2LoginSpec.

To Reproduce

@EnableWebFluxSecurity
@Import({

		CustomOAuth2UserService.class,

})
@Slf4j
@SpringBootApplication(scanBasePackages = "none")
public class InconsistentOAuth2UserDetailsServiceApp {
	public static class CustomOAuth2UserService extends DefaultOAuth2UserService {

	}

	@Bean
	public SecurityWebFilterChain configureUi(ServerHttpSecurity http) {

		return http.build();
	}

	public static void main(String[] args) {
		SpringApplication.run(InconsistentOAuth2UserDetailsServiceApp.class);
	}

}

Expected behavior
Given a bean of type ReactiveOAuth2UserService, it should be injected to all components needed one, especially OidcReactiveOAuth2UserService, as it is done for OAuth2LoginReactiveAuthenticationManager

[blacelle]

Workaround: provide a OidcReactiveOAuth2UserService bean with relevant ReactiveOAuth2UserService:

	@Bean
	public OidcReactiveOAuth2UserService oidcReactiveOAuth2UserService(
			ReactiveOAuth2UserService<OAuth2UserRequest, OAuth2User> oauth2UserService) {
		OidcReactiveOAuth2UserService oidcReactiveOAuth2UserService = new OidcReactiveOAuth2UserService();

		oidcReactiveOAuth2UserService.setOauth2UserService(oauth2UserService);

		return oidcReactiveOAuth2UserService;
	}