修复BUG:费用类型的ERP会计科目为空时出纳回调失败问题

cost-service/src/main/java/com/blt/other/module/cost/service/impl/cost/AbstractCostService.java

@@ -467,7 +467,7 @@ public abstract class AbstractCostService implements CostService {
             List<NetsuiCostinfoDto> netsuiCostInfoDtos = new ArrayList<>();
             //费用系统信息
             NetsuiCostinfoDto feeSysInfo = new NetsuiCostinfoDto(
-                    costTypeResult.getNsAccountingSubjectId().toString(),
+                    costTypeResult.getNsAccountingSubjectId() != null ? costTypeResult.getNsAccountingSubjectId().toString() : "0",
                     costDomain.getAmount().toString(),
                     costDomain.getCostReason()
             );