Opt-in to telemetry example

[friedbunny]

How to provide an opt-in to or independent toggle for Mapbox telemetry collection is not well documented or obvious. Given that not using our ℹ️ button (and its integrated telemetry opt-out) is a common use-case, we should provide an example of how to continue to offer end-users control over their privacy and help developers conform to our terms of service.

/cc @mapbox/maps-ios @rclee @jc-clark @malwoodsantoro