e2e Test for OAuth logins
Add end to end test coverage for logging in via OAuth for multiple providers.
See: gitlab-com/gl-infra/production#649 (closed)
Supported providers: https://docs.gitlab.com/ee/integration/omniauth.html#supported-providers
Issue for enabling Google OAuth on staging: https://gitlab.com/gitlab-com/gl-infra/infrastructure/issues/6146
Edited by Sanad Liaquat