fix: 添加获取task需求节点的时候，列表为空的返回情况

web/src/main/java/cn/seecoder/web/service/impl/tree/TreeNodeServiceImpl.java

@@ -173,6 +173,9 @@ public class TreeNodeServiceImpl implements TreeNodeService {
      * 信息填入
      */
     private List<TreeNodeVO> getTreeNodeVOS(List<TreeNodePO> nodesPO) {
+        if (nodesPO.size()==0){
+            return new ArrayList<>();
+        }
         int projectId = nodesPO.get(0).getProjectId();
         List<Integer> userIds = nodesPO.stream().filter(x->x.getProcessorId()!=null).map(TreeNodePO::getProcessorId).collect(Collectors.toList());
         Map<Integer,String> usernameMap = userIds.size() == 0? new HashMap<>() : userMapper.selectByIds(userIds).stream().collect(Collectors.toMap(UserPO::getId, UserPO::getUsername));