bugfix - triple protocol request doesn't carry attachment such as group or version.

[ztelur]

Which issue(s) this PR fixes:

• triple protocol request doesn't carry attachment such as group or version.

Special notes for your reviewer:

the client code in dubbo3_invoker is like below, so server use metadata.FromIncomingContext to get attachments from context

// append interface id to ctx
gRPCMD := make(metadata.MD, 0)
for k, v := range invocation.Attachments() {
if str, ok := v.(string); ok {
	gRPCMD.Set(k, str)
	continue
}
if str, ok := v.([]string); ok {
	gRPCMD.Set(k, str...)
	continue
}
logger.Warnf("triple attachment value with key = %s is invalid, which should be string or []string", k)
}
ctx = metadata.NewOutgoingContext(ctx, gRPCMD)
ctx = context.WithValue(ctx, tripleConstant.InterfaceKey, di.BaseInvoker.GetURL().GetParam(constant.InterfaceKey, ""))