message: Fix table visualization when no index is present
diff: @@ -16,8 +16,10 @@ prepare_visualization x max_rows = Helpers.recover_errors <| case x of
  Dataframe_Table.Table _ ->
  dataframe = x.take_start max_rows
  all_rows_count = x.row_count
  - indices = [dataframe.index] . catch _-> []
  - here.make_json dataframe indices all_rows_count
  + included_rows = dataframe.row_count
  + index = dataframe.index.catch _->
  + Dataframe_Column.from_vector "" (Vector.new included_rows i->i)
  + here.make_json dataframe [index] all_rows_count
  Database_Table.Table _ _ _ _ ->
  # Materialize a table with indices as normal columns (because dataframe does not support multi-indexing).
  