feat: Add Portuguese (pt-PT) language to the Checkout

[rodrigobarona]

Closes #

Is a new feature to add the Portuguese language (pt-PT) to the checkout

What I did

Following the other translations, translate from English to Portuguese Portugal, the locale.

How to test

Set by the language_code to pt for Portuguese

Checklist

• [X] Make sure your changes are tested (stories and/or unit, integration, or end-to-end tests).
• [X] Make sure to add/update documentation regarding your changes.
• [x] You are NOT deprecating/removing a feature.