Fix potential nil access

app/views/devise/sessions/new.html.erb

@@ -1,6 +1,6 @@
 <%
   # TODO remove when https://github.com/hotwired/turbo/issues/203 is fixed
-  enable_turbo = !session[:user_return_to].match?('/discourse/connect')
+  enable_turbo = !session[:user_return_to] || !session[:user_return_to].match?('/discourse/connect')
 %>
 
 <%= render HeaderCompactComponent.new(title: "Log in") %>