Add Hungarian ("hu") locale support to Watson Assistant Web Chat, including full localization of date/time formats and calendar UI elements

We would like to request support for the Hungarian ("hu") locale in Watson Assistant Web Chat, including full localization of built-in UI elements such as date/time formatting and the calendar component.

Currently, the web chat supports the following locales via updateLocale():
en, fr, de, es, it, ja, ko, pt-BR, zh-CN, zh-TW

Hungarian ("hu") is not included in this list, and therefore:
- Date and time formats default to English (AM/PM format)
- Calendar elements (month names, weekdays) cannot be displayed in Hungarian
- Certain built-in UI labels (e.g. "You") appear in the selected locale language when using a workaround (e.g. German or French), resulting in a mixed-language user experience

We have explored the available options:
- Using instance.updateLocale("hu") → not supported
- Loading Hungarian dayjs locale at page level → not applied by the web chat
- Using supported locales (e.g. "de", "fr") → results in non-Hungarian UI elements
- Using language packs → does not affect date/time or calendar localization

As a result, it is currently not possible to provide a fully Hungarian user experience in the web chat UI.

This requirement comes from a live banking use case (Erste Bank Hungary Zrt.), based on direct customer feedback. From a native-language usability and accessibility perspective, proper localization of date/time formats and calendar elements is essential.

How it should work:
- Support "hu" (or "hu-HU") as a valid locale in updateLocale()
- Ensure that date/time formats follow Hungarian standards (24-hour format, local date format)
- Ensure that the calendar component displays Hungarian month and weekday names
- Keep language pack compatibility for additional UI text customization

This enhancement would significantly improve usability for Hungarian-speaking users and support compliance requirements in EU-regulated environments.