cloud_llm_client: Move `Plan` type into `cloud_api_types` (#47778)

This PR moves the `Plan` type out of `cloud_llm_client` and into
`cloud_api_types`.

Release Notes:

- N/A
4723dbe696Marshall Bowers committed on 1/27/2026, 3:58:05 PM· committed by GitHubparent73bb119
20 files changedLine totals unavailable