[Feature Request] use own style.json instead of mapbox access token

[anderl80]

For plotly scatter mal plots:

I'd wish the package also offered the possibility to use a self defined style.json like when you use Mapbox natively in JS. Using this specification (and using OSM tiles) makes the mapbox_access_token obsolete.

plotly/plotly.py#1431

[etpinard]

Thanks for posting. We'll make that simpler this spring.

In the meantime you can get this to work by providing a dummy mapbox access token: https://codepen.io/etpinard/pen/KbxgXb

[etpinard]

Related #3173, #2988