WIP: Lists the most vulnerable projects on the Group Security Dashboard

What does this MR do?

This MR introduces a list of projects that are most affected / at risk to the Group Security Dashboard. This benefits users by enabling them to quickly navigate to the project security dashboards and focus their efforts there.

Screenshots

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

Availability 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

Closes #11190 (closed)