Remove the duplicated spans in the otel logging

[tasn]

All of the logs are duplicated and show both under span and under spans. This is unnecessary and wasteful, we can just keep spans.

We just need to verify that spans.0 is always equivalent to span, because if the ordering is reversed it would suck a bit (because it'll be hard to know the top level).

What's the common way of doing it?

[tasn]

Speak with @svix-james too, maybe it's not wanted/needed, though I think it is?