open_ai: Remove list of supported countries (#29347)

This PR removes the list of supported countries from the `open_ai`
crate, as it is no longer referenced in this repo.

Release Notes:

- N/A
b54bbebc03Marshall Bowers committed on 4/24/2025, 2:55:37 PM· committed by GitHubparent8bb7a1f
2 files changedLine totals unavailable