Always retain raster tile cache control data

[andycalder]

This fixes #10491. It ensures that cache control headers are passed back from getImage() regardless of whether arrayBufferToImage() or arrayBufferToImageBitmap() is used internally.

Launch Checklist

• briefly describe the changes in this PR
• write tests for all new functionality
• manually test the debug page
• apply changelog label ('bug', 'feature', 'docs', etc) or use the label 'skip changelog' (I don't have privileges for this)
• add an entry inside this element for inclusion in the mapbox-gl-js changelog: <changelog>Fixed a bug where raster tile expiry data was not being retained.</changelog>

[arindam1993]

Thanks for the contribution @andycalder , I ran a quick test across Chrome, Firefox and Safari on macOS since they have varying ImageBitMap support and the caching behavior works as expected!