Set TimeNotBuiltin msgpack option directly without using BasicHandle

Prevents a situation where when attempting to decode a string into a nil
interface, the decoded value would be the encoded slice of bytes instead
of the string we need.

engine/storage_interface.go

@@ -265,9 +265,7 @@ func NewCodecMsgpackMarshaler() *CodecMsgpackMarshaler {
 	mh := new(codec.MsgpackHandle)
 	mh.MapType = reflect.TypeOf(map[string]any(nil))
 	mh.RawToString = true
-	mh.BasicHandle = codec.BasicHandle{
-		TimeNotBuiltin: true,
-	}
+	mh.TimeNotBuiltin = true
 	return &CodecMsgpackMarshaler{mh}
 }