Added buttonCount control (2-6 buttons) to ButtonGroup Playground in Storybook

[liuliu-dev]

Part of #5262

Rollout strategy

• None; Only storybook playground changes.

Testing & Reviewing

Merge checklist

• Added/updated tests
• Added/updated documentation
• Added/updated previews (Storybook)
• Changes are SSR compatible
• Tested in Chrome
• Tested in Firefox
• Tested in Safari
• Tested in Edge
• (GitHub staff only) Integration tests pass at github/github (Learn more about how to run integration tests)

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Latest commit: 1e14913

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Pull Request Overview

This PR enhances the ButtonGroup Playground story in Storybook by adding a dynamic buttonCount control that allows users to interactively adjust the number of buttons displayed (ranging from 2 to 6 buttons).

Key Changes:

• Modified the Playground story to dynamically generate buttons based on a buttonCount parameter
• Added buttonCount control to Storybook argTypes with constraints (min: 2, max: 6, step: 1)