fix(with/etcd): 修改Etcd配置为空时的处理逻辑

当Etcd配置或端点为空时，将panic改为直接返回，避免程序崩溃

with/etcd.go

@@ -13,7 +13,7 @@ import (
 
 func Etcd(cfg *conf.EtcdConf, cli *clientv3.Client) {
 	if cfg == nil || len(cfg.Endpoints) == 0 {
-		panic("Etcd endpoints is Empty!")
+		return
 	}
 
 	etcdCfg := clientv3.Config{