Admin: Error when trying to edit the title of a section

[martanducas]

Describe the bug
When I try to edit the title of a section, an error occurs and the participatory area disappears.

To Reproduce

1. As admin, upload a new PDF document and go to "Edit participatory areas"
2. Create a participatory area and click to "Save changes!"
3. Click to the recently created area and try to set a new title
4. When clicking "Save", the participatory area disappears and the platform starts getting a little crazy :'(

Expected behavior
Editing the title of a section should not delete the participatory area or make the platform go crazy.

Screenshots
https://github.com/stadtluzern/decidim-pdf-consultations/assets/72607737/d5fc256c-0821-475c-ba54-faf937173afe

Stacktrace
workshops.pokecode.net-1700596062704.log

Extra data
URL: https://workshops.pokecode.net/assemblies/test-gpc
Browser: Chrome & Firefox

[martanducas]

Bug reported here: openpoke/decidim-module-participatory-documents#109