clean rails performance page security route check

config/routes.rb

@@ -4,12 +4,12 @@
   root to: 'home#index'
   mount LetterOpenerWeb::Engine, at: "/letter_opener" if Rails.env.development?
 
-  constraints(lambda { |req| req.session[:user].admin? }) do
-    mount RailsPerformance::Engine, at: '/rails/performance'
-  end
-
-  constraints(lambda { |req| !req.session[:user].admin? }) do
-    get '/rails/performance', to: redirect('/login?redirect=/rails/performance')
+  constraints(lambda { |req| req.session[:user].present? || req.session[:user].nil? }) do
+    if req.session[:user]&.admin?
+      mount RailsPerformance::Engine, at: '/rails/performance'
+    else
+      get '/rails/performance', to: redirect('/login?redirect=/rails/performance')
+    end
   end
 
   get '/tools', to: 'home#tools'