[Docs]: Remove pass-through layout

[amannn]

Link to page

https://next-intl.dev/docs/environments/error-files#catching-non-localized-requests

Describe the problem

With global-not-found.js, there should no longer be a need for a pass-through layout. We can probably already update the docs and examples for this.

[stefanprobst]

i did run into vercel/next.js#86095 with global-not-found.

[amannn]

@stefanprobst Oh that's interesting, thanks for sharing! I've subscribed to your bug repro and will follow along …