"br log status " does return error message after started an incremental backup task ,but It does not work normally actually.

## Bug Report

Please answer these questions before submitting your issue. Thanks!

### 1. Minimal reproduce step (Required)

Step 1: Firstly configure log-backup.temp-path which tidb does not have write permissions, for example /root

Step 2: Start a incremental backup task
tiup br log start --task-name='pitr' --pd=192.168.56.102:2379 --storage="/backup/pitr"

Step 3: Query incremental backup task status
tiup br log status --pd=192.168.56.102:2379

Step4: “status: ● NORMA” will confuse users ,Because the task is unnormmal. We can find messages in tikv.log as follows:
[2024/01/19 09:29:50.036 +08:00] [WARN] [errors.rs:171] ["backup stream meet error"] [verbose_err="Io(Os { code: 13, kind: PermissionDenied, message: \"Permission denied\" })"] [err="I/O Error: Permission denied (os error 13)"] [context="failed to register backup stream task pitr to router: ranges not found"]

### 2. What did you expect to see? (Required)
I think the status should return unnormal or error .

### 3. What did you see instead (Required)
You always only find "status: ● NORMAL" beside the gap will more and more bigger.

### 4. What is your TiDB version? (Required)
mysql> select tidb_version();
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tidb_version() |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Release Version: v6.5.5
Edition: Community
Git Commit Hash: 71bcc44f77a37cfb0a6dc3660e092c78c1e46acb
Git Branch: heads/refs/tags/v6.5.5
UTC Build Time: 2023-09-18 10:20:26
GoVersion: go1.19.12
Race Enabled: false
TiKV Min Version: 6.2.0-alpha
Check Table Before Drop: false
Store: tikv |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.01 sec)