Add test coverage for non-visible turbo-cable-streams-ource tags

Author: excid3

test/dummy/app/views/messages/show.html.erb

@@ -1,6 +1,6 @@
 <h1>Message #<%= @message.id %></h1>
 
-<%= turbo_stream_from @message %>
+<%= turbo_stream_from @message, style: "display: none" %>
 
 <div id="<%= dom_id @message %>">
   <%= render @message %>