Deploys defaulting to Fly-hosted Builders

This incident has been resolved.

We are seeing improvements in Depot builder provision times and are switching the default deploy strategy back to them. We will continue to monitor builder performance closely. Users with a preference can trigger a Fly builder based deploy with `fly deploy --depot=false` or use `fly deploy --depot=true` to force a depot-based deployment.

We are investigating delays provisioning Depot backed builders for deploys. We have switched the default `fly deploy` strategy to use fly hosted builders at this time. Users can still trigger a depot based deploy with `fly deploy --depot=true`