Fix Denmark's postal code field label

[jeffersontuc]

What is the purpose of this pull request?

ATTS

The "postal code" translation (Postnumre) for Denmark should be made trough the messages file, similar to es.json or pt-BR.json.

How should this be manually tested?

• Access trackfieldeu cart
• Change shipping-preview selected country to Dinamarca
• Check if the postal code label shows a proper label

Screenshots or example usage

Before

After

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Requires change to documentation, which has been updated accordingly.

[vtex-io-ci-cd]

Hi! I'm VTEX IO CI/CD Bot and I'll be helping you to publish your app! 🤖

Please select which version do you want to release:

• Patch (backwards-compatible bug fixes)

• Minor (backwards-compatible functionality)

• Major (incompatible API changes)

And then you just need to merge your PR when you are ready! There is no need to create a release commit/tag.

• No thanks, I would rather do it manually 😞

[GeorgeLimaDev]

Nice catch. LGTM. 🚀

[GeorgeLimaDev]

Please @jeffersontuc, be kind to consider #658 as well when moving on with this PR. Thank you.