Productivity Analytics: Order projects by last activity

What does this MR do?

Since gitlab.com doesn't use elastic search, we cannot find GitLab (EE) in the project dropdown on the Productivity Analytics page even if we increase the list to 50 since we rank it lower and don’t do exact matching.

This MR adds the order_by=last_activity query parameter to the dropdown as suggested in #32330 (comment 219293942) which will list gitlab in the results.

This is behind the productivity_analytics feature flag.

Screenshots

No screenshots available as this will mainly influence gitlab.com.

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