SUGCON24 EU: Agenda and Sessions rendering can not be added in Experience Editor

[gkLeo]

Describe the bug When adding the Agenda or Sessions in the Experience Editor, an error will occur. A PR is created for this issue #451

To Reproduce Steps to reproduce the behavior:

1. Go to Content Editor
2. Right-click on '/sitecore/content/Sugcon2024/EU/Home'
3. Click 'Experience Editor'
4. Click 'Add here' in 'Main' placeholder
5. Click 'EVENTS', then select 'Agenda' or 'Sessions', click 'Select'
6. See error

Expected behavior 'Select the Associated Content' dialog box should appear.

Screenshots