WikiEduDashboard: Activity tab does cannot fetch revisions from wikisource.org

What is happening?

The Activity tab of this course does not show any activity: https://outreachdashboard.wmflabs.org/courses/Igbo_Wikimedians_User_Group/Introduction_to_Igbo_Wikisource/activity/recent

There are JS errors in the console; it looks like CORS is stopping the requests to the Wikisource API.

Additional context

wikisource.org is a separate wiki (for multilingual source texts) from the individual language versions of Wikisource like en.wikisource.org. In contrast to www.wikidata.org, the canonical URL for this wiki does not include the www. subdomain. However, the requests from the Activity tab are going to www.wikisource.org rather than just wikisource.org. It’s like that the CORS errors are because of this.