[BR:PD:ErrPDBatchScanRegion] failed to scan region, retrying

## Bug Report

Please answer these questions before submitting your issue. Thanks!

### 1. Minimal reproduce step (Required)
use br restore data from v8.1.2 to master

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

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

`[2025/03/10 11:57:02.732 +00:00] [WARN] [split.go:254] ["failed to scan region, retrying"] [error="region 15043270's endKey not equal to next region 19117209's startKey, endKey: 7480000000000000FFA75F728000000196FFB51F0A0000000000FA, startKey: 7480000000000000FFA75F728000000196FFB5383A0000000000FA, region epoch: conf_ver:101 version:24411 conf_ver:89 version:24411 : [BR:PD:ErrPDBatchScanRegion]batch scan region"] [regionLength=3101044]`

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

From

> Release Version: v8.1.2
> Edition: Community
> Git Commit Hash: a21402da4ab5b342d2bb4da5bff954eecc7a20e1
> Git Branch: heads/refs/tags/v8.1.2
> UTC Build Time: 2025-03-07 01:19:19
> GoVersion: go1.21.10
> Race Enabled: false
> Check Table Before Drop: false
> Store: tikv

TO

> Release Version: v9.0.0-alpha-381-g739a934
> Edition: Community
> Git Commit Hash: 739a934f631eb413ff3b150b0a7fc9db55eefcbd
> Git Branch: HEAD
> UTC Build Time: 2025-03-10 06:19:26
> GoVersion: go1.23.7
> Race Enabled: false
> Check Table Before Drop: false
> Store: tikv