Allow deleting sections from preview view after participatory text import

Is your feature request related to a problem? Please describe.
After importing a participatory text, drafts (proposals) are generated for each section and you can do changes/improvements to the resulting sections before publishing.

If you want to merge two sections you can copy the content of one section into the other section, but it is not possible to delete the now empty section, so you can't save the result because of validation errors (empty fields).

Describe the solution you'd like
I have already added a delete button to each section and could do a pull request in GitHub. But as far as I understand I should first create a discussion here about this idea?

Screenshot (External link)

Describe alternatives you've considered
Deleting all empty drafts after clicking on "publish". But this would be less intuitive and harder to solve.

Additional context
I read a few times that the draft preview view is confusing.

Examples:

• https://github.com/stadtluzern/decidim-ocl/issues/51
• https://meta.decidim.org/processes/roadmap/f/122/proposals/16221

Does this issue could impact on users private data?
No, it is just a simple delete button in the user interface.

Funded by
This change is part of our project improving the participatory texts module, funded by netidee in Austria: https://www.netidee.at/decidimaustria