Inconsistent behaviour between Scala2/3 DeriveSchema for simpleEnum annotations

[googley42]

I think is an unrelated existing bug in Scala 3 DeriveSchema whereby it adds simpleEnum annotation at the top level of the EnumN schema when one of the cases is a simple enum - however this does not happen with the Scala 2 macro. I think the Scala2 behavior is correct ie this should be a the leaf schema level.