[BUG] "Token required - not valid tokenless upload" for PR from a fork on open source repo

[Luthaf]

Describe the bug

PR to the metatensor/metatrain repo from a fork fail to upload coverage with a Token required - not valid tokenless upload error.

The token is set to not required in https://app.codecov.io/account/gh/metatensor/org-upload-token

To Reproduce

Fork https://github.com/metatensor/metatrain and send a PR upstream.

Expected behavior

Coverage upload that comes from PR from a fork should work on this repository.

Regression

unsure, we recently started using forks instead of all putting branches on the same repo.

Screenshots
If applicable, add screenshots to help explain your problem.

Product Area

coverage

Versions

• OS: [e.g. linux, ubuntu@v24, macos arm64, windows]
• Git Host: [e.g. GitHub, GitLab, Bitbucket]
• CI/CD: [e.g. GitHub Actions, CircleCI]
• Uploader: [e.g. codecov-action@v5.3.1, codecov-circleci-orb@v5.2.0, codecov-cli@v10.0.1, uploader@v0.8.0]

Commit and CI link

metatensor/metatrain#631

Additional context

This seems very similar to #1782 which required manual intervention by the codecov team.