`scattermapbox` restyle bug

Regression introduced in [`v2.16.0`](https://github.com/plotly/plotly.js/releases/tag/v2.16.0) likely related to #5827.
```
Plotly.restyle(gd, 'marker.colorscale', 'Portland');
```
does not update the markers on the map!

cc: https://github.com/plotly/dash/issues/2343