refactor(validator): 更新字符串工具类导入路径

- 将StringUtils的导入从com.kingdee.util更改为kd.bos.util
- 保持原有功能不变，仅调整依赖包路径

code/wtc/nckd-jxccl-wtc/src/main/java/nckd/jxccl/wtc/wtabm/web/validate/VaApplySubmitValidator.java

@@ -1,11 +1,11 @@
 package nckd.jxccl.wtc.wtabm.web.validate;
 
-import com.kingdee.util.StringUtils;
 import kd.bos.dataentity.entity.DynamicObject;
 import kd.bos.entity.ExtendedDataEntity;
 import kd.bos.entity.validate.AbstractValidator;
 import kd.bos.logging.Log;
 import kd.bos.logging.LogFactory;
+import kd.bos.util.StringUtils;
 import nckd.jxccl.wtc.wtabm.web.service.VaApplyValidateService;
 
 /**