Do not use non-recommended styleSet in samples

[OEvgeny]

Fixes #5022

Changelog Entry

Description

This improves samples so they don't include non-recommended createStyleSet usage to avoid new users confusion.

Specific Changes

• Updated wording to align with current API
• Updated Sample 6 to use preferred styleOptions API

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• [ ] I have added tests and executed them locally
• [ ] I have updated CHANGELOG.md
• [ ] I have updated documentation

Review Checklist

This section is for contributors to review your work.

• [ ] Accessibility reviewed (tab order, content readability, alt text, color contrast)
• [ ] Browser and platform compatibilities reviewed
• [ ] CSS styles reviewed (minimal rules, no z-index)
• [ ] Documents reviewed (docs, samples, live demo)
• [ ] Internationalization reviewed (strings, unit formatting)
• [ ] package.json and package-lock.json reviewed
• [ ] Security reviewed (no data URIs, check for nonce leak)
• [ ] Tests reviewed (coverage, legitimacy)