add index failed with error “Error 1105 (HY000): get member failed” when inject network partition between pd leader and all pd follower

## Bug Report

Please answer these questions before submitting your issue. Thanks!

### 1. Minimal reproduce step (Required)
1、with tidb_enable_dist_task='off'
2、run sysbench
3、add index for one of table
4、inject network partition between pd leader and all pd follower

tidb logs：
[tidb-0.tar.gz](https://github.com/pingcap/tidb/files/15060096/tidb-0.tar.gz)
[tidb-1.tar.gz](https://github.com/pingcap/tidb/files/15060099/tidb-1.tar.gz)

### 2. What did you expect to see? (Required)
add index can success

### 3. What did you see instead (Required)
add index failed with error “Error 1105 (HY000): get member failed”

add index failed at 2024-04-19 23:47:03: Error 1105 (HY000): get member failed
operatorLogs:
[2024-04-19 23:46:49] ###### start adding index
ALTER TABLE `sbtest1` ADD INDEX `index_test_1713541609102`(`c`)
[2024-04-19 23:46:49] ###### wait for ddl job finish

tidb log
`[2024/04/19 23:47:02.012 +08:00] [ERROR] [terror.go:324] ["encountered error"] [error="close tcp 10.233.126.115:4000->172.16.6.4:47418: use of closed network connection"] [stack="github.com/pingcap/tidb/parser/terror.Log\n\t/workspace/source/tidb/parser/terror/terror.go:324\ngithub.com/pingcap/tidb/server.(*Server).onConn\n\t/workspace/source/tidb/server/server.go:688"]
[2024/04/19 23:47:02.166 +08:00] [INFO] [pd_service_discovery.go:439] ["[pd] cannot update member from this address"] [address=http://tc-pd:2379] [error="[PD:client:ErrClientGetLeader]get leader from leader address don't exist error"]
[2024/04/19 23:47:02.878 +08:00] [INFO] [coprocessor.go:1288] ["[TIME_COP_PROCESS] resp_time:893.815869ms txnStartTS:18446744073709551615 region_id:46244 store_addr:tc-tikv-0.tc-tikv-peer.endless-ha-test-add-index-tps-7569302-1-197.svc:20160 kv_process_ms:878 kv_wait_ms:0 kv_read_ms:0 processed_versions:410870 total_versions:410871 rocksdb_delete_skipped_count:0 rocksdb_key_skipped_count:410870 rocksdb_cache_hit_count:5 rocksdb_read_count:1500 rocksdb_read_byte:40060712"]
[2024/04/19 23:47:03.166 +08:00] [ERROR] [pd.go:307] ["fail to create pd client"] [error="[PD:client:ErrClientGetMember]get member failed"]
[2024/04/19 23:47:03.166 +08:00] [ERROR] [backend_mgr.go:96] ["[ddl-ingest] build ingest backend failed"] ["job ID"=473] [error="[Lightning:PD:ErrCreatePDClient]create pd client error: [PD:client:ErrClientGetMember]get member failed"]
[2024/04/19 23:47:03.166 +08:00] [WARN] [terror.go:242] ["Unknown error class"] [class=PD]
[2024/04/19 23:47:03.166 +08:00] [INFO] [ddl_worker.go:956] ["[ddl] DDL job is cancelled normally"] [worker="worker 2, tp add index"] [error="[Lightning:PD:ErrCreatePDClient]create pd client error: [PD:client:ErrClientGetMember]get member failed"]
[2024/04/19 23:47:03.168 +08:00] [INFO] [ddl_worker.go:603] ["[ddl] finish DDL job"] [worker="worker 2, tp add index"] [job="ID:473, Type:add index, State:cancelled, SchemaState:none, SchemaID:88, TableID:245, RowCount:0, ArgLen:6, start time: 2024-04-19 23:46:49.096 +0800 CST, Err:[PD:client:ErrClientGetMember]get member failed, ErrCount:1, SnapshotVersion:0, UniqueWarnings:0"]
[2024/04/19 23:47:03.185 +08:00] [INFO] [ddl.go:1181] ["[ddl] DDL job is failed"] [jobID=473]`

### 4. What is your TiDB version? (Required)
./tidb-server -V
Release Version: v7.1.5
Edition: Community
Git Commit Hash: https://github.com/pingcap/tidb/commit/f4faa508e58826d8c44382ac429717290271e7e2
Git Branch: HEAD
UTC Build Time: 2024-04-19 10:49:04
GoVersion: go1.20.10
Race Enabled: false
TiKV Min Version: 6.2.0-alpha
Check Table Before Drop: false
Store: unistore
2024-04-20T07:08:24.815+0800