fix(rebase): rebase a dossier when its repetition had been removed on newer version does not crash

app/models/procedure_revision_change.rb

@@ -7,6 +7,7 @@ class ProcedureRevisionChange
   def label = @type_de_champ.libelle
   def stable_id = @type_de_champ.stable_id
   def private? = @type_de_champ.private?
+  def child? = @type_de_champ.child?
 
   def to_h = { op:, stable_id:, label:, private: private? }