Add e2e tests for billable users in subscription page

What does this MR do and why?

part of #362533 (closed)

• Add e2e tests for
  • Remove cloud license
  • License usage count with seeded license data (gitlab-qa change in gitlab-qa!988 (merged) and gitlab-qa!979 (merged))

Screenshots or screen recordings

Pipeline result: https://gitlab.com/gitlab-org/gitlab-qa-mirror/-/jobs/2592385645

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.