Allow OIDC routes to be localizable

[aduth]

🛠 Summary of changes

Fixes an issue where trying to change the language on the OpenID Connect logout confirmation screen results in a 404 page, by allowing the pages to be localizable (within the :locale block in the routes.rb file).

The only other routes defined out side the :locale block are not meant to be human-facing.

📜 Testing Plan

1. Prerequisite: Have the OIDC sample application running in a separate process
2. Visit http://localhost:9292
3. Click "Sign in"
4. Complete sign-in
5. At SP, click "Sign out"
6. Observe OIDC logout screen
7. Change language of the page using the language selector

Before: You'd see a 404
After: You see the page translated in the language you're expecting

Verify there are no regressions in other places which reference these URLs.

Example: http://localhost:3000/.well-known/openid-configuration

👀 Screenshots

Before	After