lightning import failed when kill pdleader

## Bug Report

Please answer these questions before submitting your issue. Thanks!

### 1. Minimal reproduce step (Required)
1、run lightning import
2、kill pdleader

case config：
- name: "ha_pdleader_kill"
warmUpTime: 1m
faultType: kill
selector: "pd(leader)"
period: "@every 3m"
faultDuration: 1m
faultTotalRunTime: 20m
lightningList: &id001
- storage: s3://benchmark/location-dumpling
s3Endpoint: http://minio.pingcap.net:9000
db: location
options: --enable-checkpoint false
config: |-
[lightning]
max-error = 9999999999
[tikv-importer]
duplicate-resolution = "record"
incremental-import = true
crc32Checksum: 2645404411
adminCheck:
- table: AreaMeshLake
indexes:
- areameshlakeid
backend: local
sortedKvDir: /tmp/sorted-kv-dir
- storage: s3://brie/lightning-mhy-100G-csv
s3Endpoint: http://minio.pingcap.net:9001
db: sysbench
backend: local
sortedKvDir: /tmp/sorted-kv-dir
options: "--enable-checkpoint false"
config: "[[mydumper.files]]\npattern = \"sysbench-schema-create.sql\"\nschema = \"sysbench\"\ntype = \"schema-schema\"\n[[mydumper.files]]\npattern = \"sysbench.user_data1-schema.sql\"\nschema = \"sysbench\"\ntable = \"user_data1\"\ntype = \"table-schema\"\n[[mydumper.files]]\npattern = \"sysbench.user_data1.000000[0-3][0-9][0-9].csv\"\nschema = \"sysbench\"\ntable = \"user_data1\"\ntype = \"csv\""
crc32Checksum: 619903217

### 2. What did you expect to see? (Required)
lightning import can success

### 3. What did you see instead (Required)
lightning import failed when kill pdleader

RunLightning: 2023-11-01 04:47:22
cmd: /tidb-lightning --tidb-host=tc-tidb.ha-test-lightning-tps-3571297-1-463 --tidb-port=4000 --backend=local --sorted-kv-dir=/tmp/sorted-kv-dir -d "s3://benchmark/location-dumpling?access-key=xxx&secret-access-key=xxx&endpoint=http://minio.pingcap.net:9000&force-path-style=true" --config tidb-lightning.toml --enable-checkpoint false
stdout: Verbose debug logs will be written to /tmp/lightning.log.2023-10-31T20.46.21Z
tidb lightning encountered error: [Lightning:PD:ErrUpdatePD]pd address (http://tc-pd-0.tc-pd-peer.ha-test-lightning-tps-3571297-1-463.svc:2379/) not available, error is Get "http://tc-pd-0.tc-pd-peer.ha-test-lightning-tps-3571297-1-463.svc:2379/pd/api/v1/config/cluster-version": dial tcp [10.233.68.14:2379](http://10.233.68.14:2379/): connect: connection refused, please check network

### 4. What is your TiDB version? (Required)
git hash：5f7b6973b0d730b446d840733f213ad6637bee1f