E2E: Remove facebook OAuth e2e spec

What does this MR do and why?

This test is currently in quarantine for a different reason however, since the Facebook OAuth functionality is deprecated, I am not sure if it makes sense to maintain this test anymore. This MR removes the test.

Related issue: gitlab-org/quality/quality-engineering/team-tasks#2194 (closed)

This will be followed by removal of related code from gitlab-qa.

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