fix(#4175): add conditions for notifier auto-configuration to check if admin server is enabled

Author: SteKoe

spring-boot-admin-server/src/main/java/de/codecentric/boot/admin/server/config/AdminServerNotifierAutoConfiguration.java

@@ -74,6 +74,8 @@
 import de.codecentric.boot.admin.server.notify.filter.web.NotificationFilterController;
 
 @Configuration(proxyBeanMethods = false)
+@Conditional(SpringBootAdminServerEnabledCondition.class)
+@ConditionalOnBean(AdminServerMarkerConfiguration.Marker.class)
 @EnableConfigurationProperties(NotifierProxyProperties.class)
 @AutoConfigureAfter({ MailSenderAutoConfiguration.class })
 public class AdminServerNotifierAutoConfiguration {