fix: fully sanitize unauthenticated client config (#13785)

Follow-up to #13714.

Fully sanitizes the unauthenticated client config to exclude much of the
users collection, including fields, etc. These are not required of the
login flow and are now completely omitted along with other unnecessary
properties.

This is closely aligned with the goals of the original PR, and as an
added bonus, makes the config _even smaller_ than it already was for
unauthenticated users.

Needs #13790.

---
- To see the specific tasks where the Asana app for GitHub is being
used, see below:
  - https://app.asana.com/0/0/1211332845301588

test/next-env.d.ts

@@ -2,4 +2,4 @@
 /// <reference types="next/image-types/global" />
 
 // NOTE: This file should not be edited
-// see https://nextjs.org/docs/app/building-your-application/configuring/typescript for more information.
+// see https://nextjs.org/docs/app/api-reference/config/typescript for more information.