FR Primitives: Add UI elements for rendering AWS WAF CAPTCHAs

### On which framework/platform would you like to see this feature implemented?

React, React Native, iOS, Android

### Which UI component is this feature-request for?

Primitive components

### Please describe your feature-request in detail.

Today, AWS WAF displays CAPTCHA challenges like presented in [this blog post](https://aws.amazon.com/blogs/security/use-aws-waf-captcha-to-protect-your-application-against-common-bot-traffic/). Users can't modify how they are rendered:
- style (colours, fonts) can't be changed
- i18n customisation is missing - there's no option to provide translations for labels of the given UI

### Please describe a solution you'd like.

I would like to use an Amplify UI element to render these CAPTCHAs that can be styled on the client side. I believe that translations and styles (anything that is not the challenge data itself) should be provided by the client/web application itself, not AWS WAF.

### We love contributors! Is this something you'd be interested in working on?

- [ ] 👋 I may be able to implement this feature request.
- [ ] ⚠️ This feature might incur a breaking change.

The issue names primitive components and the React, React Native, iOS, and Android platforms, but no files, tests, or entry points. Start by reviewing the existing primitive-component areas and the linked AWS WAF CAPTCHA example, then clarify platform scope, styling, and translation boundaries. Done means a supported Amplify UI element renders the CAPTCHA with client-controlled styles and labels.

Written by the indexing model from the issue text.