Throw error on URI mismatch

[PaulAsjes]

Fixes https://github.com/workos/authkit-nextjs/issues/40

In the case where you have:

• Middleware auth mode enabled
• Redirect URL in the middleware matcher
• Don't have the redirect URL in the unauthenticatedPaths array

You'd get stuck in a login loop as you'd be redirected to AuthKit before the session can be set establishing that you've already logged in.

This adds a check and throws an error in that case.