Corresponding JH branch cannot be found due to API token mismatch

This was discovered at !99479 (comment 1217621140) where I figured we're using PROJECT_TOKEN_FOR_CI_SCRIPTS_API_USAGE to access the private JH mirror, which does not work because it's a project token for GitLab, not a project token for the private mirror.

We need to fix the token to use one that has the permission.