fix(avis#instruction): use safer claiment.email with a simple helper

app/helpers/avis_helper.rb

@@ -0,0 +1,5 @@
+module AvisHelper
+  def safe_claimant_email(claimant)
+    claimant&.email || "inconnu"
+  end
+end

app/views/experts/avis/instruction.html.haml

@@ -7,7 +7,7 @@
     %h1.tab-title Donner votre avis
     %h2.claimant
       Demandeur :
-      %span.email= @avis.claimant.email
+      %span.email= safe_claimant_email(@avis.claimant)
       %span.date Demande d’avis envoyée le #{l(@avis.created_at, format: '%d/%m/%y')}
     %p.introduction= @avis.introduction
 

app/views/experts/shared/avis/_list.html.haml

@@ -9,7 +9,7 @@
         .width-100
           %h2.claimant
             = "#{t('claimant', scope: 'activerecord.attributes.avis')} :"
-            %span.email= (avis.claimant.email == current_expert.email) ? 'Vous' : avis.claimant.email
+            %span.email= (safe_claimant_email(avis.claimant) == current_expert.email) ? 'Vous' : safe_claimant_email(avis.claimant)
             - if avis.confidentiel?
               %span.confidentiel
                 = t('confidentiel', scope: 'activerecord.attributes.avis')