Contribution criteria tree-item shows two items as selected

[GCHQ-Developer-741]

Summary of the bug

When clicking the contribution criteria tree-item on the site, both that and the "how to contribute" item show the selected state, and the wrong item receives focus.

🪜 How to reproduce

Tell us the steps to reproduce the problem:

1. Go to https://mi6.github.io/ic-design-system-githubpages/branches/v3.0.0/develop/community
2. Click on the contribution criteria tree item
3. See the error

📸 Screenshots or code

🧐 Expected behaviour

The correct tree-item should show the selected state and receive focus.

[cd3859]

Issue resolved with #1384