Fix the status exception when no user ever logged in to the application

backend/core/management/commands/status.py

@@ -26,7 +26,7 @@ def handle(self, *args, **kwargs):
             x["last_login"] for x in User.objects.all().values("last_login")
         )
         self.stdout.write(
-            f"created_at={created_at.strftime('%Y-%m-%dT%H:%M')} last_login={last_login.strftime('%Y-%m-%dT%H:%M')} "
+            f"created_at={created_at.strftime('%Y-%m-%dT%H:%M')} last_login={last_login.strftime('%Y-%m-%dT%H:%M') if last_login else last_login} "
             + f"users={nb_users} first_logins={nb_first_login} libraries={nb_libraries} "
             + f"domains={nb_domains} projects={nb_projects} assets={nb_assets} "
             + f"threats={nb_threats} functions={nb_functions} measures={nb_measures} "