fix: attach 8-bit path segments to session info

[mmatl]

Having the 8-bit path segment flag attached to the message router prevents you from connecting to multiple adapters with varying support for 16-bit path segments. For our use case, it makes more sense to attach that flag to the SessionInfo object. Since the SessionInfo is used when creating the EPath for forward open requests, we can dynamically modify the EPath format on a per-session / per-adapter basis.

This is a breaking change, so let me know if there's something you'd like modified here.