message: fix: replace `read_only` with `writable`
diff: @@ -299,7 +299,8 @@ function onValueChanged (valueId, node, changed) {
  data = { time: Date.now(), value: tmpVal }
  }
  - if (!valueId.read_only && !this.topicValues[topic]) {
  + // valueId is writable, subscribe for updates
  + if (valueId.writable && !this.topicValues[topic]) {
  const levels = topic.split('/').length
  if (this.topicLevels.indexOf(levels) < 0) {
  