Deprecate/replace AuthRequest.validate()

[eurekaP]

How can I deprecate or replace AuthRequest.validate() on this library?

[ProLord007]

There's 2 ways to validate requests using AuthRequest:

authRequest.validate();
authRequest.validateUser();

validate() returns the session, and validateUser() returns the session and user. It isn't really useful to have both, and if you're using SvelteKit, using both in a single load function flow can lead to 2 database calls (depending on the other).

I think we should replace validate() with the current validateUser(), so it returns both user and session.