[bs-138] Add @OnManagementContext for management beans

User adds @OnManagementContext to a bean or @Configuration and
it should be included in the management context (if there is one)
whether it is the main context or a child.

Makes it easy to secure the management endpoints and keep
the rest open (see actuator-ui-sample).

[#50721675]

spring-bootstrap/src/main/java/org/springframework/bootstrap/context/annotation/OnExpressionCondition.java

@@ -65,7 +65,7 @@ public class OnExpressionCondition implements Condition {
 		if (resolver == null) {
 			resolver = new StandardBeanExpressionResolver();
 		}
-		Boolean result = (Boolean) resolver.evaluate(value, expressionContext);
+		boolean result = (Boolean) resolver.evaluate(value, expressionContext);
 		if (logger.isDebugEnabled()) {
 			logger.debug(checking + "Finished matching and result is matches=" + result);
 		}