### Check for existing issues

- [x] I have searched the existing issues and checked that my issue is not a duplicate.

### What happened?

When `store_prompts_in_spend_logs: true` is enabled, the `/spend/logs/ui` endpoint returns full `messages`/`response` content to callers with the `proxy_admin` role, but **omits the `messages` and `response` fields entirely** from the JSON payload when the same exact log row (same `request_id`) is requested by a caller with the `internal_user` role — even when that `internal_user` is the owner of the request.

This makes the Admin UI's Request Logs page show "Request/Response Data Not Available" for `internal_user` accounts on requests that do have stored prompt/response data. The banner's suggested fix ("enable prompt storage") is misleading in this case, since storage is already enabled and working (proven by the `proxy_admin` view of the identical row).

I expected an `internal_user` to be able to view the full request/response content of their **own** requests when `store_prompts_in_spend_logs` is enabled, consistent with the fact that they can already see every other field for that same row (tokens, cost, duration, tags, model, team, etc.)…