added optional gradient. added halo on active. added aria labels to a…

[GregLongo]

…ll inputs

Closes #

---Note: This is an interview assignment for UX Engineer Position --

Changes

Modified Range Slider component :

• Added subtle gradient effect with toggle in storybook
• Added halo effect around slider handle on active state for greater visibility on mobile and behind desktop cursor
• Added aria-labels on inputs for screen readers

Screenshots

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Checklist

Check all that apply

• [ ] Updated documentation to reflect changes
• [ ] Added entry to top of Changelog with link to PR (not issue)
• [ ] Tests pass
• [ ] Peer reviewed and approved
• [ x] Signed CLA (if not already signed)