Add the ability to ignore specific browser errors for a spec (#31436)

spec/system/log_out_spec.rb

@@ -24,6 +24,9 @@ describe 'Log out' do
 
   describe 'Logging out from the JS app', :js, :streaming do
     it 'logs the user out' do
+      # The frontend tries to load announcements after a short delay, but the session might be expired by then, and the browser will output an error.
+      ignore_js_error(/Failed to load resource: the server responded with a status of 422/)
+
       visit root_path
 
       within '.navigation-bar' do