Make progress animation respect `$enable-transitions` and `prefers-reduced-motion` media query

Created by: MartijnCuppens

Fixes #25709 (closed)

Prevent progress animation if transitions are disabled or reduce motion is enabled. If $enable-transitions is false:

• @keyframes progress-bar-stripes and .progress-bar-animated are not rendered.

If reduced motion is enabled:

• The animation is disabled thanks to animation: none;