Attachments can not be deleted

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Describe the bug

If I want to delete an attachment, I can click on the delete button.
However, that never deletes the attachment but keeps it around. You can still restore it and it will still show in the list of attachments to insert into the description.

To Reproduce
Steps to reproduce the behavior:

1. Upload Attachment
2. Click on delete
3. Attachment will be flagged as deleted
4. But Attachment wont go away

Expected behavior

If the attachment is deleted, it should not be visible anymore in the list of attachments to insert.

Furthermore there should be a method to actually delete attachments. Maybe have a second button to finally delete the attachment if wanted.

Screenshots
Attachment is "deleted"

but still selectable:

NC 19.0.4 / Deck 1.1.2

First reproduce the listed upload, delete, and insert-selection steps in the attachment interface. Trace the attachment delete flow and the list of attachments available for insertion; done means deleted attachments are no longer selectable, with the intended permanent-deletion behavior clarified and covered by the relevant checks.