Latest version concept was deprecated upstream

[schlessera]

The AMP project has deprecated the concept of latestVersion and -latest binaries: https://github.com/ampproject/amphtml/issues/36749

Right now, we use that data for the AutoExtensions transformer to figure out which version of a component to pull in.

Instead of relying on the latestVersion, we'll have to pick the most appropriate one from the list of "available" versions. We need to figure out what that means for experimental versions, as we want to default to stable versions unless otherwise requested.