Stop prebuilds from running when a project is added on a new team with no paid plans or available credits

[gtsiolis]

Bug description

Prebuilds for some projects on teams with no active billing or available credits continue to run against the user who added the project. One case involves a GitLab repository where the individual user added the repository as a project, using a webhook, the default method for enabling prebuilds for GitLab repositories.

See relevant discussion (internal). Cc @jldec @svenefftinge

Steps to reproduce

Haven't tested this, but this could be probably reproduced by adding a GitLab repository as a project on a new team with no active paid plan, which enables prebuilds for that project.

[jldec]

The current behavior was by design, making prebuilds usable by members of the community, even when those prebuilds are managed through a project in a team with no payment configured.

Once attribution is limited to teams only (see #15665) and we have a mechanism to keep supporting OSS projects, this behavior will be revisited.

[geropl]

Should be covered by: #16347

[gtsiolis]

Thanks for coming back to this, @geropl! 🏀