Update button alignment in OtpAuth component to be centered (#3650)

* Update button alignment in OtpAuth component to center for improved UX

Author: hajinsuha1

packages/template-retail-react-app/app/components/otp-auth/index.jsx

@@ -302,7 +302,7 @@ const OtpAuth = ({
                             )}
 
                             {/* Buttons */}
-                            <HStack spacing={4} width="100%" justifyContent="flex-end">
+                            <HStack spacing={4} width="100%" justifyContent="center">
                                 {!hideCheckoutAsGuestButton && (
                                     <Button
                                         onClick={handleCheckoutAsGuest}