cubicweb #4912946 [hooks] don't insert use_email relation if the entity on either side is going away [validation pending]

prioritynormal
typebug
done in3.19.9
load0.500
load left0.000
closed by#c6dfa0d6b7d1 [hooks] don't insert use_email relation if the entity on either side is going away
patch[hooks] don't insert use_email relation if the entity on either side is going away [applied]