chore(logic): add a translation for empty rule

app/models/logic/empty_operator.rb

@@ -1,5 +1,5 @@
 class Logic::EmptyOperator < Logic::BinaryOperator
-  def to_s(_type_de_champs = []) = "empty operator"
+  def to_s(_type_de_champs = []) = I18n.t('logic.empty_operator')
 
   def type(_type_de_champs = []) = :empty
 

config/locales/models/logic/en.yml

@@ -1,3 +1,4 @@
 en:
   logic:
     empty: empty member
+    empty_operator: empty operator

config/locales/models/logic/fr.yml

@@ -1,6 +1,7 @@
 fr:
   logic:
     empty: un membre vide
+    empty_operator: un opérateur vide
     is: Est
     is_not: N’est pas
     operators: