Fix archived parameter for Group API's projects endpoint

What does this MR do?

This MR aligns the "archived" parameter behavior in the Groups API with the docs; if the parameter should "Limit by archived status", it should not have a default value set. This was fixed in the Projects API by this MR, but the Groups API's projects endpoint was left with the old behavior.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

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