cubicweb-email #120097 required sender relation may make removal for user impossible [resolved]

if we have:

user -- use_email --> email email -- sender --> email

and we try to remove user, the email is removed as well (composite relation), but then a validation error occurs since email has no more sender.

prioritynormal
typebug
done in1.4.1
load0.500
load left0.000
closed by<not specified>