Add scrollbar styles export

[Kamalpannu]

Checklist (Check off all the items before submitting)

• [x] Build process is done without errors. All tests pass in the /lib directory.
• [x] Self-reviewed the code before submitting.
• [x] Meets accessibility standards.
• [x] Added/updated documentation to /website as needed.
• [x] Added/updated tests as needed.

Purpose Fix the issue with missing scrollbarStyles export so it can be imported correctly in index.ts.

Description

• Added scrollbarStyles export in src/index.ts.
• Verified TS build passes and website builds correctly.
• Ensured all tests in /lib pass successfully.

Screenshots Not applicable.

Additional context The import ./styles/scrollbarStyles was missing, causing TS build failures in the library.

**Closes #2190 **