cubicweb #3766717 cw_rest_attr_info should only consider required attributes [validation pending]

it doesn't make much sense to use a non-required attribute as rest path

prioritynormal
typebug
done in3.19.4
load0.500
load left0.000
closed by#8f4b15e5b300 [entities] cw_rest_attr_info() should only consider required attributes (closes #3766717)
patch[entities] cw_rest_attr_info() should only consider required attributes (closes #3766717) [applied]