cubicweb #10294761 avoid using InternalManager when sending notification [validation pending]

else we may leak information due to security (un)restriction.

Moreover some legacy code may expect an actual user, not an internal manager, while the current code will use an internal manager by default.

prioritynormal
typebug
done in3.23.0
load left0.000
closed by#ebb6809659a4 [notification] avoid using InternalManager when we've got a CWUser
patch[notification] avoid using InternalManager when we've got a CWUser [applied]