message: fix: pie chart multiple groupbys
diff: @@ -1527,10 +1527,10 @@ class DistributionPieViz(NVD3Viz):
  if df.empty:
  return None
  metric = self.metric_labels[0]
  - df = df.pivot_table(index=self.groupby, values=[metric])
  - df.sort_values(by=metric, ascending=False, inplace=True)
  - df = df.reset_index()
  - df.columns = ["x", "y"]
  + df = pd.DataFrame(
  + {"x": df[self.groupby].agg(func=", ".join, axis=1), "y": df[metric]}
  + )
  + df.sort_values(by="y", ascending=False, inplace=True)
  return df.to_dict(orient="records")
  