message: fix: unicode word cloud example
  closes
diff: @@ -75,7 +75,13 @@ def load_unicode_test_data():
  slice_data = {
  "granularity_sqla": "dttm",
  "groupby": [],
  - "metric": "sum__value",
  + "metric": {
  + "expressionType": "SIMPLE",
  + "column": {"column_name": "value", "type": "INT"},
  + "aggregate": "SUM",
  + "label": "value",
  + "optionName": "metric_11",
  + },
  "row_limit": config.get("ROW_LIMIT"),
  "since": "100 years ago",
  "until": "now",
  