fix：增加导出功能

cjl

2023-11-15 df67fe187fae9ce9f486ea2f14c95a14d843e4a1

 screen-manage/src/main/java/com/moral/api/util/CompareFieldUtils.java

@@ -70,7 +70,7 @@
                else
                    result.setNewData(newDataObj.toString());

                if(oldDataObj==null)
                if(oldDataObj==null||oldDataObj.equals(""))
                    result.setOldData("null");
                else
                    result.setOldData(oldDataObj.toString());