GH-3425: Remove mngmt gauges from CtxClosedEvent

Fixes #3425

It turns out that `IntegrationManagementConfigurer.destroy()` is still too
late to remove `gauges` and Micrometer tries to gather them on application
context close, when many beans are already destroyed

* Catch `ContextClosedEvent` in the `IntegrationManagementConfigurer`
and removed `gauges` from there
* Remove `destroy()` impl since it is out of use already:
the `IntegrationManagementConfigurer` is not supposed to be in the
target application directly, so it looks safe to remove the `DisposableBean`
altogether

**Cherry-pick to `5.3.x` & `5.2.x`**

# Conflicts:
#	spring-integration-core/src/main/java/org/springframework/integration/config/IntegrationManagementConfigurer.java

Author: artembilan

spring-integration-core/src/main/java/org/springframework/integration/config/IntegrationManagementConfigurer.java

@@ -28,11 +28,12 @@
 
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.BeanNameAware;
-import org.springframework.beans.factory.DisposableBean;
 import org.springframework.beans.factory.SmartInitializingSingleton;
 import org.springframework.beans.factory.config.DestructionAwareBeanPostProcessor;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
+import org.springframework.context.ApplicationListener;
+import org.springframework.context.event.ContextClosedEvent;
 import org.springframework.integration.core.MessageSource;
 import org.springframework.integration.support.management.IntegrationManagement;
 import org.springframework.integration.support.management.IntegrationManagement.ManagementOverrides;
@@ -61,7 +62,7 @@
 @SuppressWarnings("deprecation")
 public class IntegrationManagementConfigurer
 		implements SmartInitializingSingleton, ApplicationContextAware, BeanNameAware,
-		DestructionAwareBeanPostProcessor, DisposableBean {
+		DestructionAwareBeanPostProcessor, ApplicationListener<ContextClosedEvent> {
 
 	private static final Log LOGGER = LogFactory.getLog(IntegrationManagementConfigurer.class);
 
@@ -468,6 +469,13 @@ private void registerComponentGauges() {
 						.build());
 	}
 
+	@Override public void onApplicationEvent(ContextClosedEvent event) {
+		if (event.getApplicationContext().equals(this.applicationContext)) {
+			this.gauges.forEach(MeterFacade::remove);
+			this.gauges.clear();
+		}
+	}
+
 	public String[] getChannelNames() {
 		return this.channelsByName.keySet().toArray(new String[0]);
 	}
@@ -518,13 +526,6 @@ public org.springframework.integration.support.management.MessageSourceMetrics g
 		return null;
 	}
 
-	@Override
-	public void destroy() {
-		this.gauges.forEach(MeterFacade::remove);
-		this.gauges.clear();
-	}
-
-
 	private static ManagementOverrides getOverrides(IntegrationManagement bean) {
 		return bean.getOverrides() != null ? bean.getOverrides() : new ManagementOverrides();
 	}