Fix flaky specs due to lack of assertions

We were optimistically assuming that the page has already loaded and
this was causing some flaky specs.

Author: forkata

templates/spec/system/authentication/checkout_spec.rb

@@ -121,11 +121,13 @@
       create(:user, email: 'email@person.com', password: 'password', password_confirmation: 'password')
       click_link 'Solidus hoodie'
       click_button 'Add To Cart'
+      expect(page).to have_text 'Shopping Cart'
 
       visit login_path
       click_link 'Forgot Password?'
       fill_in 'spree_user_email', with: 'email@person.com'
       click_button 'Reset my password'
+      expect(page).to have_text('If an account with that email address exists')
 
       # Need to do this now because the token stored in the DB is the encrypted version
       # The 'plain-text' version is sent in the email and there's one way to get that!