[WIP] CI: enable EPID RA

[OverOrion]

This PR is basically the same as #1224 but the target branch is different.

Draft until #1222 gets merged.

[OverOrion]

The tests are failing because GHA secrets are not available in forked repositories.

With the exception of GITHUB_TOKEN, secrets are not passed to the runner when a workflow is triggered from a forked repository.

https://docs.github.com/en/actions/security-guides/encrypted-secrets#using-encrypted-secrets-in-a-workflow

Switching to pull_request_target would solve it, but it has some security implications, which we should discuss first.
https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#pull_request_target

[OverOrion]

Superseded by #1286