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

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