feat(components): [select] accessibility enhancement

[tolking]

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Description

🤖 Generated by Copilot at ceea20a

This pull request enhances the accessibility and customization of the select and scrollbar components. It adds aria-* attributes and roles to the select component and its options, and uses the useId and useAttrs hooks to generate unique ids and forward inherited attributes. It also adds style and class props to the scrollbar component and refactors some of its template and logic. It updates the test cases accordingly.

Related Issue

Fixes #14437.

Explanation of Changes

🤖 Generated by Copilot at ceea20a

• Add style and class props to scrollbar component to enable customization (link)
• Bind style and class props to root element of scrollbar component and pass inherited attributes to child component (link, link, link, link, link)
• Generate and bind accessible attributes for option and select components using useId hook (link, link, link, link, link, link, link, link, link, link, link, link, link, link)
• Test accessibility of select component in packages/components/select/__tests__/select.test.ts (link)
• Remove outdated comment in packages/components/select/src/select.vue (link)

[github-actions]

[github-actions]

🧪 Playground Preview: https://element-plus.run/?pr=14503
Please comment the example via this playground if needed.

[btea]

LGTM