Cache-defeating URL parameters aren't passed to sprite URLs

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**mapbox-gl-js version**: 0.41.0

### Steps to Trigger Behavior

1. Call mapboxgl.map({ ... style: 'mapbox://styles/user/abc123?update=1 } )
2. The style file is fetched from: api.mapbox.com/styles/v1/user/abc123.json?update=1&access_token=...

### Expected Behavior

1. The sprite file is fetched from api.mapbox.com/styles/v1/user/abc123/sprite@2x.json?update=1&access_token=...

### Actual Behavior

1. The sprite file is fetched from api.mapbox.com/styles/v1/user/abc123/sprite@2x.json?access_token=...

This means that when you update icons through the Studio interface, it often takes a long time before you can see them in your maps, because the files get cached along the way, and there's really no workaround.

Start at the mapboxgl.map style-loading entry point and trace how the style URL is turned into the sprite URL. Verify that query parameters such as update=1 are retained in the sprite request, and confirm the resulting request avoids stale cached sprite data.

Written by the indexing model from the issue text.