import into command don't need to check log backup any more

## Bug Report

Please answer these questions before submitting your issue. Thanks!

### 1. Minimal reproduce step (Required)

In a cluster with log backup turned on

```sql
import into tb_backup from select * from tb;
```

### 2. What did you expect to see? (Required)

Since this version support lightning import with log backup turned on. The import command should not report error.

### 3. What did you see instead (Required)

```sql
mysql> import into tb_backup from select * from tb;
ERROR 8173 (HY000): PreCheck failed: found PiTR log streaming task(s): [log-integrated-backup-schedule-s3],
```

### 4. What is your TiDB version? (Required)

```sql
mysql> select @@version;
+-------------------------------------+
| @@version |
+-------------------------------------+
| 8.0.11-TiDB-v8.5.0-20250117-f069f0b |
+-------------------------------------+
1 row in set (0.00 sec)
```