refactor(dossier): use champ id as champ attributes key

app/views/shared/dossiers/_edit.html.haml

@@ -35,10 +35,9 @@
         dossier.procedure.groupe_instructeurs.order(:label).map { |gi| [gi.label, gi.id] },
         { include_blank: dossier.brouillon? }
 
-    = f.fields_for :champs, dossier.champs do |champ_form|
-      - champ = champ_form.object
-      = render partial: "shared/dossiers/editable_champs/editable_champ",
-        locals: { champ: champ, form: champ_form }
+    - dossier.champs.each do |champ|
+      = fields_for champ.input_name, champ do |form|
+        = render partial: "shared/dossiers/editable_champs/editable_champ", locals: { form: form, champ: champ }
 
     - if !dossier.for_procedure_preview?
       .dossier-edit-sticky-footer

app/views/shared/dossiers/editable_champs/_editable_champ.html.haml

@@ -8,5 +8,6 @@
     = render partial: 'shared/dossiers/editable_champs/champ_label', locals: { form: form, champ: champ, seen_at: defined?(seen_at) ? seen_at : nil }
   - if champ.type_champ == "titre_identite"
     %p.notice  Carte nationale d’identité (uniquement le recto), passeport, titre de séjour ou autre justificatif d’identité. Formats acceptés : jpg/png
-  = render partial: "shared/dossiers/editable_champs/#{champ.type_champ}",
-    locals: { champ: champ, form: form }
+
+  = form.hidden_field :id, value: champ.id
+  = render partial: "shared/dossiers/editable_champs/#{champ.type_champ}", locals: { form: form, champ: champ }