add index failed with error “Error 8247 (HY000): Ingest failed: concurrency quota exceeded” or “Error 1105 (HY000): write /var/lib/tidb-data/tmp_ddl-4000/685/b5a95334-0640-57cd-8ed4-9c0267440793.sst/a580b32c-640f-4e93-940d-f701629935ac.sst: transport endpoint is not connected” when injection tidb io delay

## Bug Report

Please answer these questions before submitting your issue. Thanks!

### 1. Minimal reproduce step (Required)
1、tidb_enable_dist_task='on'
2、run sysbench
3、add index
4、injection tidb temp-dir io delay 1s lasts for 3mins

### 2. What did you expect to see? (Required)
one failed：
add index failed at 2025-03-02 01:46:39: Error 8247 (HY000): Ingest failed: concurrency quota exceeded
operatorLogs:
[2025-03-02 01:45:46] ###### start adding index
ALTER TABLE `sbtest1` ADD INDEX `index_test_1740851146297`(`c`)
[2025-03-02 01:45:46] ###### wait for ddl job finish
[tidb-0.log.zip](https://github.com/user-attachments/files/19086658/tidb-0.log.zip)
[tidb-1.log.zip](https://github.com/user-attachments/files/19086721/tidb-1.log.zip)

other failed：
add index failed at 2025-03-02 15:59:49: Error 1105 (HY000): write /var/lib/tidb-data/tmp_ddl-4000/685/b5a95334-0640-57cd-8ed4-9c0267440793.sst/a580b32c-640f-4e93-940d-f701629935ac.sst: transport endpoint is not connected
operatorLogs:
[2025-03-02 15:58:54] ###### start adding index
ALTER TABLE `sbtest1` ADD INDEX `index_test_1740902334663`(`c`)
[2025-03-02 15:58:54] ###### wait for ddl job finish

[tidb-0.log.zip](https://github.com/user-attachments/files/19087036/tidb-0.log.zip)
[tidb-1.log.zip](https://github.com/user-attachments/files/19087038/tidb-1.log.zip)

### 3. What did you see instead (Required)
add index can succeed

### 4. What is your TiDB version? (Required)
./tidb-server -V
Release Version: v7.5.6
Edition: Community
Git Commit Hash: 55e84ff57f0f577478c45e8ca64c2f37f4472d2f
Git Branch: HEAD
UTC Build Time: 2025-02-28 10:15:04
GoVersion: go1.21.13
Race Enabled: false
Check Table Before Drop: false
Store: unistore
2025-03-02T01:36:16.187+0800