i18n: fix enum values for Dossier.state

According to Rails i18n guide, enum values should be localized
as `<model>/<enum>`, not as sub-values to the attribute.

This fixes an exception in administrate when displaying a Dossier
in the Manager.

Note: we need to change the way GraphQL attributes are generated, because
`AASM::Core::State#display_name` doesn’t honor the `model/attribute.value`
convention (and instead tries to localize as `model.attribute/value`).
So instead we lookup the localized name using ActiveRecord.

config/locales/models/dossier/fr.yml

@@ -9,20 +9,16 @@ fr:
         montant_projet: 'Le montant du projet'
         montant_aide_demande: "Le montant d’aide demandée"
         date_previsionnelle: "La date de début prévisionnelle"
-        state: &state
-          brouillon: "Brouillon"
-          en_construction: "En construction"
-          en_instruction: "En instruction"
-          accepte: "Accepté"
-          refuse: "Refusé"
-          sans_suite: "Classé sans suite"
+        state: "État"
         autorisation_donnees: Acceptation des CGU
-        state/brouillon: Brouillon
-        state/en_construction: En construction
-        state/en_instruction: En instruction
-        state/accepte: Accepté
-        state/refuse: Refusé
-        state/sans_suite: Sans suite
+      dossier/state: &state
+        brouillon: "Brouillon"
+        en_construction: "En construction"
+        en_instruction: "En instruction"
+        accepte: "Accepté"
+        refuse: "Refusé"
+        sans_suite: "Classé sans suite"
       traitement:
-        state:
-          <<: *state
+        state: "État"
+      traitement/state:
+        <<: *state