fix(设备管理): 导入设备时，忽略空字符串的配置

jetlinks-manager/device-manager/src/main/java/org/jetlinks/community/device/web/excel/DeviceExcelInfo.java

@@ -38,7 +38,7 @@ public class DeviceExcelInfo {
     private String state;
 
     public void config(String key, Object value) {
-        if (value == null) {
+        if (value == null || value instanceof String && !StringUtils.hasText((String) value)) {
             return;
         }
         configuration.put(key, value);