add pdf to pjs export

spec/factories/dossier.rb

@@ -201,6 +201,15 @@ FactoryBot.define do
       end
     end
 
+    trait :with_pdf_export do
+      after(:create) do |dossier, _evaluator|
+        dossier.pdf_export_for_instructeur.attach(
+          io: StringIO.new('Hello World'),
+          filename: 'export.pdf'
+        )
+      end
+    end
+
     trait :with_justificatif do
       after(:create) do |dossier, _evaluator|
         dossier.justificatif_motivation.attach(