collab: Remove `GET /billing/preferences` endpoint (#34566)

This PR removes the `GET /billing/preferences` endpoint, as it has been
moved to `cloud.zed.dev`.

Release Notes:

- N/A
048dc47d87Marshall Bowers committed on 7/16/2025, 5:55:01 PM· committed by GitHubparentffc69b0
4 files changedLine totals unavailable