Adds Cantonese Chinese (zh-hk) locale

[antkwok]

Enables the Cantonese Chinese locale in the frontend, including adding it to supported locales, locale maps, and including the message translations.

Thank you for creating a PR! We appreciate your contribution to Hi.Events.

To make the process as smooth as possible, please ensure you've read the contributing guidelines before proceeding.

Please include a summary of the changes and the issue being fixed or the feature being added. The more detail, the better!

Checklist

• I have read the contributing guidelines.
• My code is of good quality and follows the coding standards of the project.
• I have tested my changes, and they work as expected.

Thank you for your contribution! 🎉

[github-actions]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[antkwok]

I have read the CLA Document and I hereby sign the CLA

[daveearley]

Awesome! Thank you very much for this contribution 😄