fix some test brittleness

app/controllers/users/registrations_controller.rb

@@ -1,3 +1,3 @@
 class Users::RegistrationsController < Devise::RegistrationsController
-    invisible_captcha only: [:create]
+    invisible_captcha only: [:create] unless Rails.env.test?
 end

test/system/sign_up_test.rb

@@ -8,9 +8,11 @@ class SignUpTest < ApplicationSystemTestCase
     fill_in "Email", with: "[email protected]"
     fill_in "Password", with: "password123", match: :prefer_exact
     fill_in "Password confirmation", with: "password123"
-    sleep 4 # The invisible_captcha bot protection will kick in if this is too quick
+
     click_on "Get Started"
 
+    assert_text "A message with a confirmation link has been sent to your email address."
+
     user = User.last
     assert_equal user.email, "[email protected]"