E2E: Remove user_access_termination_spec from reliable suite

What does this MR do?

qa/qa/specs/features/api/1_manage/user_access_termination_spec.rb intermittently fails due to #403001 (closed), see #386671 (comment 1333297103) for more details

This MR removes this spec from the reliable suite so that it does not continually block deployments while the bug is being fixed.

E2E Test Failure issue(s)

Failure in api/1_manage/user_access_termination... (#386671 - closed)

• Related bug: Move ProcessScanResultPolicyWorker for multiple... (#403001 - closed)

Check-list

• General code guidelines check-list
  • Code review guidelines
  • Style guides
• Quarantine test check-list
  • Follow the Quarantining Tests guide.
  • Confirm the test has a quarantine: tag with the specified quarantine type.
  • Note if the test should be quarantined for a specific environment.
  • (Optionally) In case of an emergency (e.g. blocked deployments), consider adding labels to pick into auto-deploy (Pick into auto-deploy priority1 severity1).
• Dequarantine test check-list
  • Follow the Dequarantining Tests guide.
  • Confirm the test consistently passes on the target GitLab environment(s).
• To ensure a faster turnaround, ask in the #quality_maintainers Slack channel for someone to review and merge the merge request, rather than assigning it directly.