fix(teacher): 修复任务详情获取失败时未跳转的问题

当获取任务详情失败时，自动跳转到任务列表页面

@@ -275,6 +275,8 @@ async function fetchData() {
             } else {
             } else {
                 upload_count.value = 0
                 upload_count.value = 0
             }
             }
+        } else {
+            $router.push('/teacher/tasks')
         }
         }
     } catch (error) {
     } catch (error) {
         console.error('Failed to fetch task details:', error)
         console.error('Failed to fetch task details:', error)