cubicweb #2409855 Author box links to None author when author has been deleted [done]

the link should not appear.

prioritynormal
typebug
done in3.15.11
load0.100
load left0.000
closed by#00c5ea2a064a [web] don't link to None in author box (when author has been deleted) (closes #2409855)
patch[web] don't link to None in author box (when author has been deleted) (closes #2409855) [applied]