修复无法获取在线状态等信息的问题

jetlinks-manager/device-manager/src/main/java/org/jetlinks/community/device/response/DeviceDetail.java

@@ -141,6 +141,7 @@ public class DeviceDetail {
                                             .stream()
                                             .map(ConfigPropertyMetadata::getProperty)
                                             .collect(Collectors.toList()))
+                         .defaultIfEmpty(Values.of(Collections.emptyMap()))
             )
             .doOnNext(tp -> {
                 setOnlineTime(tp.getT2());