Fix capybara screenshot attachment

This commit fixes the way we generate our attachment tag during
a test failure. It is now using the same configuration than QA.

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spec/support/capybara.rb

@@ -170,14 +170,16 @@ RSpec.configure do |config|
     Capybara.raise_server_errors = false
 
     example.run
+  ensure
+    Capybara.raise_server_errors = true
+  end
 
+  config.append_after do |example|
     if example.metadata[:screenshot]
       screenshot = example.metadata[:screenshot][:image] || example.metadata[:screenshot][:html]
+      screenshot&.delete_prefix!(ENV.fetch('CI_PROJECT_DIR', ''))
       example.metadata[:stdout] = %{[[ATTACHMENT|#{screenshot}]]}
     end
-
-  ensure
-    Capybara.raise_server_errors = true
   end
 
   config.after(:example, :js) do |example|