[E2E] PROMOTE TO BLOCKING: security_reports_spec.rb

What does this MR do?

Promotes the following e2e tests to the blocking bucket:

1. Govern Security Reports displays security reports in the group security dashboard | Testcase | Spec metrics

This MR was created based on data from reliable e2e test report: #477169 (closed)

(This MR was automatically generated by gitlab_quality-test_tooling at 2024-08-05 02:06:14 UTC)