Force raster maps to load as PNGs to preserve transparency

raster.js

      // Force load raster as PNG (Safari will use JPG otherwise) to preserve transparency
      map.addSource('noaa_map', {
        type: 'raster',
        tiles: [
          `https://api.mapbox.com/v4/cnndigital.7d5hl52y/{z}/{x}/{y}.png?access_token=${mapboxgl.accessToken}`,
        ],
      });

      map.addLayer({
        id: 'raster-layer',
        type: 'raster',
        source: 'noaa_map',
        minzoom: 0,
        maxzoom: 8,
      }, 'road-simple');