I’ve seen projects where testing is done in prod and also projects where API keys for some external services (e.g. Mapbox) are shared across prod and dev. Or cases where credentials end up in Git repos (edit: wrote GitHub originally, but meant typically non-public repos on any platform) due to ease of use and how inadequate secret management solutions can be.
Luckily that’s not the majority of projects, but I bet it happens a lot more elsewhere. Definitely a bunch for your average outsourced/freelance/scrappy/non-funded project.
Whether anyone will actually use your secrets or even code that’s sent to these large AI shops, though, that’s another question. You might as well question using GitHub cause it’s owned by M$.