Added E2E test for Secure group security dashboard

What does this MR do?

Added an end to end test verifying the Secure group security dashboard.

Also added necessary page objects and QA selectors to support this test.

Additionally renamed project_security_dashboard_spec.rb to security_reports_spec.rb to reflect that not only projects are included in this file.

This will accomplish one of the six tasks within gitlab-org/quality/testcases#7 (closed).

Moves forward OKR: gitlab-com/www-gitlab-com#4344 (closed).

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance and testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team

Closes #9192 (moved)