fix: area speech bbubble appears twice

[jannisvisser]

Describe your changes

PR resolves #1575.

Checklist before requesting a review

• I have performed a self-review of my code
• I have added tests wherever relevant
• I have made sure that all automated checks pass before requesting a review

Notes for the reviewer

1. First observation is that this bug derives from our mock setup, where all mock data for all admin-areas is repeated for every event, instead of trimming down each event's mock data to only the admin-areas of that event. The reason for this is because it's easier this way, because we'd have to go through all the mock files to do this trimming. Still, it would be better to do that. This same situation should not occur in production, because there the pipeline will actually only upload the admin-areas belonging to that event.
2. That being said, this can and should also additionally be solved by filtering in the GET query code on event if available. This solves the issue, and is the better fix anyway. So opting to not also clean up the mock data. Feel free to disagree.