Normalize Mapbox URLs within styles

[aparlato]

Followup to #208

We now normalize all style URL's, but those using a Mapbox protocol often still contain sprite and glyphs fields that also use that protocol.

We should normalize these URLs as well so that if a user chose to, they could render that style with another renderer that doesn't handle that protocol (eg Maplibre, Maptiler).

Noting that this is a followup issue because the places/ways this needs to change are different from the ways we normalize a style URL.

We should investigate whether it makes more sense to:

• alter the stylesheet itself and make sure that is being passed around
• add custom protocols to Maplibre and Maptiler renderers to handle mapbox:// protocols the same as Mapbox does