bug: etcd Timeout configuration will never take effect

[zxyao145]

ETCDConfig.Timeout is not assigned a value from conf, resulting in the timeout in the configuration file never taking effect.

source code: https://github.com/api7/apisix-seed/blob/bd8fb778b32a3c18a01685fb88729935307ef54f/internal/conf/conf.go#L102C1-L109C2