Fix Contribution Disclaimer english markdown URL if broken

Users are expected to see a contribution disclaimer message whenever they visit any of the contribution sites on /ja-JP, and may choose to click a url on the disclaimer to switch back to the english site. The url to switch back has been broken.

This issue is to Confirm if the error still exists (not reproducible in Translation Preview environment but in local)

See related: #203 (closed)

See the following screenshot from Translation Preview environment:

CleanShot 2025-10-20 at 18.22.08.gif