Release testing instructions for WC Payments 4.9.0

Support Platform Checkout from Checkout Blocks

• Firstly ensure that everything works fine on the shortcode checkout page.
• Edit your Checkout page and instead of shortcode-checkout select the Checkout block.
• Go to the merchant store, add some products to the cart and go to the checkout page (having Checkout Blocks)
• Enter an existing Platform Checkout user email, it should prompt the OTP modal. Filling in the correct OTP should redirect to the Platform Checkout page.
• Entering a non-existing Platform Checkout user email should do nothing.