Unquarantine e2e billable user spec

What does this MR do and why?

Addresses #366093 (closed)

• With !91308 (merged) and gitlab-qa!1000 (merged) merged in, we now should be able to have stable runs for this spec

Screenshots or screen recordings

Pipeline result

• https://gitlab.com/gitlab-org/gitlab-qa-mirror/-/jobs/2725277300 ✅
• https://gitlab.com/gitlab-org/gitlab-qa-mirror/-/jobs/2724820297 ✅
• https://gitlab.com/gitlab-org/gitlab-qa-mirror/-/jobs/2728984128 ✅

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.