Display archived groups when no active groups exist

[timstott]

Description

The list of archived groups isn't displayed on the groups page when there are no active groups.

🤖 I’ve added tests to verify that expected elements render correctly in the DOM. I used AI to generate the initial boilerplate, as I’m not yet familiar with writing tests in the Next.js framework. There’s also a question of whether Cypress would be preferable to introduce end-to-end tests for a broader regression prevention.

Demo

Before	After

Checklist

• I have read CONTRIBUTING.md in its entirety
• I have performed a self-review of my own code
• I have added unit tests to cover my changes
• The last commit successfully passed pre-commit checks
• Any AI code was thoroughly reviewed by me