Introduced in cec68b3e2c,
this is flaky because if you click the back button before
the route is fully transitioned to the loaded thread,
we end up going to the history _before_ the thread list,
which ends up being the channel.
We need to make sure that everything is loaded for the
thread first, meaning the skeleton is not there.
Also exclude some noise from the capybara logs (image load failures)
ccdc0822a8