chore(manager): link email users to events

app/lib/mailjet/api.rb

@@ -1,6 +1,6 @@
 class Mailjet::API
   def properly_configured?
-    [Mailjet.config.api_key, Mailjet.config.secret_key].all?(&:present?)
+    Mailjet.respond_to?(:config) && [Mailjet.config.api_key, Mailjet.config.secret_key].all?(&:present?)
   end
 
   # Get messages sent to a user through SendInBlue.

app/views/manager/users/emails.html.erb

@@ -77,6 +77,8 @@
   </p>
 <% end %>
 
+<%= link_to "Voir aussi les événements d'email", manager_email_events_path("search" =>  EmailEvent.pseudonymize_email(@user.email)) %>
+
   <h2 style="font-size: 1.3em; margin: 24px 0 8px 0">Problèmes potentiel</h2>
 
   <% if @user.confirmed? %>