JS chart deserializer keeps unrecognized x_scale and y_scale

Python `LineChart(..., x_scale='not-a-scale')` is `ScaleType.UNKNOWN`. JS `ScaleType` in packages/code-interpreter-js/src/charts.ts has no UNKNOWN, and `deserializeChart` for line/scatter returns `{ ...data }`, so `x_scale` stays `'not-a-scale'`. ChartType already has UNKNOWN on the default branch.