Adds testCheckoutPaymentMethodSelectionAndAddressAlterar, exercising
CheckoutView's payment-method row selection and the address picker's
"Alterar" entry point without ever tapping "Confirmar e Pagar" -
deliberately not submitting a real order (explicit user direction:
cover the screen, don't create real order data in the QA account).
Extracted the shared reach-checkout steps from
testAddProductToCartAndReachCheckout into a private helper,
reachCheckoutWithOneItem, reused by both tests.
Fixed the same "not hittable" Back-button bug (already documented in
UITestSupport.swift) inline here too - tapping a Back button that
exists but is mid pop-transition throws a fatal, uncatchable failure;
needs an .isHittable check with a short poll, not just .exists.
Verified stable across 2 consecutive class-level runs.
77bf276a5f