ping request should not be forwarded

[rleungx]

Bug Report

Here is a log from 1e:

[2025/01/24 12:59:19.617 +00:00] [ERROR] [middleware.go:150] ["request failed"] [error="[PD:http:ErrSendRequest]Get \"https://mussel-prod-replace-pd-0.mussel-prod-replace-pd-peer.tidb-mussel-prod-replace.
svc.us-east-1a.mussel-prod-replace.tidb.musta.ch:2379/pd/api/v1/ping\": net/http: cannot rewind body after connection loss: Get \"https://mussel-prod-replace-pd-0.mussel-prod-replace-pd-peer.tidb-mussel-p
rod-replace.svc.us-east-1a.mussel-prod-replace.tidb.musta.ch:2379/pd/api/v1/ping\": net/http: cannot rewind body after connection loss"]

The ping request shouldn't be forwarded.