admin: fix pending demandes

fetch email with map

app/controllers/manager/demandes_controller.rb

@@ -50,7 +50,7 @@ module Manager
     def pending_demandes
       already_approved_emails = Administrateur.eager(:user)
         .where(users: { email: demandes.map { |d| d[:email] } })
-        .pluck(:email)
+        .map(&:email)
 
       demandes.reject { |demande| already_approved_emails.include?(demande[:email]) }
     end