Backport Bugzilla 1834307 and hide smooth-scroll UX

links

• yay FF115+ 1832598 Default enable smooth scrolls when resisting fingerprinting
• not verified 1834307 Smooth scrolls are disabled if the user prefers-reduced-motion regardless of fingerprint resistance
  • you need to restart the browser for changes to take effect
• test (until I add it to TZP): https://dlrobertson.com/examples/scrollinto-view-scrollend.html