fix: data races when accessing `github.com/fatedier/frp/client.(*Service).ctl` (#2891)
fix: data races when accessing `github.com/fatedier/frp/client.(*Service).ctl` (#2891)

* fix: data race in client/service.go

* review fixes
fatedier/frp,fatedier/frp,fatedier/frp,fatedier/frp