message: [dashboard] make "Total Stored Txn" accurate
  By utilizing "latest_transaction_version" gauge metric instead of "commited_txn" counter.
diff: "tableColumn": "",
  "targets": [
  {
  - "expr": "avg(storage{op=\"committed_txns\"})",
  + "expr": "max(storage_gauge{op=\"latest_transaction_version\"}) + 1",
  "format": "time_series",
  "instant": true,
  "intervalFactor": 1,
  