sessionAuthenticator ignores databaseID

[ehpi]

The SessionAuthenticatable protocol provides a static sessionAuthenticator() function to which a databaseID can be passed as an optional argument:

let protected = app.grouped(
    app.session.middleware,
    User.sessionAuthenticator(.someDatabase)
)

But this argument is ignored by the DatabaseSessionAuthenticator implementation, which causes an internal server error unless the database in which the User model lives is also the default database.