Update test to correct name of metric for request that returns a 401

The request is being made to '/' and, while the application does have
a mapping for '/', that mapping is not looked for before Spring
Security's filter rejects the request with a 401. This means that the
request is considered to be unmapped and this is reflected in the
metric's name.

See #1331 and #1333

spring-boot-samples/spring-boot-sample-actuator/src/test/java/sample/actuator/UnsecureManagementSampleActuatorApplicationTests.java

@@ -79,7 +79,7 @@ public class UnsecureManagementSampleActuatorApplicationTests {
 		assertEquals(HttpStatus.OK, entity.getStatusCode());
 		@SuppressWarnings("unchecked")
 		Map<String, Object> body = entity.getBody();
-		assertTrue("Wrong body: " + body, body.containsKey("counter.status.401.root"));
+		assertTrue("Wrong body: " + body, body.containsKey("counter.status.401.unmapped"));
 	}
 
 }