qps drop more than 2 mins and also affect pitr and cdc lag when injection pd leader io delay 500ms or 1s or io hang due to a circuit breaker mechanism which is by design

## Bug Report

### What did you do?
1、run tpcc
2、inject pd leader io delay 500ms

### What did you expect to see?
qps can recover within 2mins

### What did you see instead?
qps drop last 4mins when injection pd leader io delay 500ms

clinic: https://clinic.pingcap.com.cn/portal/#/orgs/31/clusters/7370231614967615066?from=1716078044&to=1716079583


2024-05-19 08:31:01
{"container":"pd","level":"INFO","namespace":"endless-ha-test-oltp-pitr-tps-7539921-1-525","pod":"tc-pd-0","log":"[server.go:1816] [\"no longer a leader because lease has expired, pd leader will step down\"]"}

The PD-0 lost its PD leader at 08:31:01

2024-05-19 08:31:13
{"container":"pd","level":"INFO","namespace":"endless-ha-test-oltp-pitr-tps-7539921-1-525","pod":"tc-pd-0","log":"[server.go:1733] [\"campaign PD leader ok\"] [campaign-leader-name=tc-pd-0]"}

At 08:31:13, since PD-0 was still the etcd leader, it was re-elected as the PD leader

2024-05-19 08:31:28
{"container":"pd","level":"INFO","namespace":"endless-ha-test-oltp-pitr-tps-7539921-1-525","pod":"tc-pd-0","log":"[server.go:1816] [\"no longer a leader because lease has expired, pd leader will step down\"]"}

However, because io chaos continued, PD-0 dropped the PD leader again at 08:31:28, and then triggered the expulsion of the etcd leader mechanism after repeated three times:

2024-05-19 08:33:22
{"container":"pd","level":"ERROR","namespace":"endless-ha-test-oltp-pitr-tps-7539921-1-525","pod":"tc-pd-0","log":"[server.go:1713] [\"campaign PD leader meets error due to etcd error\"] [campaign-leader-name=tc-pd-0] [error=\"[PD:server:ErrLeaderFrequentlyChange]leader tc-pd-0 frequently changed, leader-key is [/pd/7370231614967615066/leader]\"]"}

2024-05-19 08:33:20
{"namespace":"endless-ha-test-oltp-pitr-tps-7539921-1-525","pod":"tc-pd-1","log":"[server.go:1733] [\"campaign PD leader ok\"] [campaign-leader-name=tc-pd-1]","level":"INFO","container":"pd"}

At 08:33:22, PD took the initiative to oust the etcd leader, and PD-1 was elected etcd and PD leader

If the etcd leader does not actively switch, the PD can only passively switch the etcd leader after three consecutive pd leader election failures

### What version of PD are you using (`pd-server -V`)?
v8.1.0
githash: fca469ca33eb5d8b5e0891b507c87709a00b0e81