cherry-pick #12201: Marker terrain occluded opacity

[karimnaaji]

Cherry-pick PR #12201 from @jacadzaca for minor review fixes and CI: including renaming of public API + unit tests.

Fixes #12123

Launch Checklist

• briefly describe the changes in this PR
• write tests for all new functionality
• document any changes to public APIs
• manually test the debug page
• apply changelog label ('bug', 'feature', 'docs', etc) or use the label 'skip changelog'
• add an entry inside this element for inclusion in the mapbox-gl-js changelog: <changelog>Allow to override marker opacity when occluded by terrain (h/t [jacadzaca](https://github.com/jacadzaca))</changelog>

[stepankuzmin]

This looks good to me 👍

[jacadzaca]

Merging this solves #12123, but the issue's not linked.

[slavanga]

@karimnaaji This is a great feature.
Is there any documentation on this? How would this be set for markers add via addLayer?

[karimnaaji]

This only affects markers set via marker.addTo. I think what you might be referring to are symbols? In that case there's no current way to adjust the opacity of occluded symbols. If that's something that might be useful to you, could you please open a feature request with the described use case?

Otherwise the documentation for this feature is here: https://docs.mapbox.com/mapbox-gl-js/api/markers/#marker#setoccludedopacity and https://docs.mapbox.com/mapbox-gl-js/api/markers/#marker-parameters.

[slavanga]

Thanks for your swift reply.
Yes, I was referring to markers added as symbols and will open a feature request.