Data frame tool results should be `orient="records"`

Current behavior is:

```python
d = pd.DataFrame({"a": [1, 2], "b": [3, 4]})
d.to_json()
#> '{"a":{"0":1,"1":2},"b":{"0":3,"1":4}}'
```

but probably should be this?

```python
d.to_json(orient="records")
#> '[{"a":1,"b":3},{"a":2,"b":4}]'
```