Update projects list to sort by the displayed timestamps

What does this MR do?

This MR updates the projects list on the dashboard so that when sorting by Last Updated or Oldest Updated, the sort order matches with the project timestamps displayed on the page. Previously the sort order was dependent solely on last_activity_at, while the displayed timestamp was the most recent of last_activity_at, last_repository_updated_at, and updated_at. This MR is continued from gitlab-foss!29859 (closed)

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
• 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