Crud, MR widget, settings block: Add preference for reduced motion

What does this MR do and why?

Crud, MR widget, settings block:

• Adds animation to chevron where missing. Will be done in gitlab-ui!5017 (merged)
• Adds check for reduced motion user settings for a11y.
• Fixes inconsistency for the divider to separate actions from the collapse/expand button in Crud vs. MR widgets
• Exposes the is_collapsible option of Crud in the Lookbook (http://gdk.test:3000/rails/lookbook/inspect/layouts/crud/default?is_collapsible=true) [JS generally doesn't work in the Lookbook unfortunately]

Screenshots or screen recordings

Before	After
prefers-reduced-motion: no-preference
prefers-reduced-motion: reduced

How to set up and validate locally

1. Open Developer tools in your browser
2. Press Command+Shift+P (Mac), type in Rendering, Enter
3. In the Rendering menu, Toggle the Emulate CSS media feature prefers-reduced-motion ooption

Tests:

1. Crud: http://gdk.test:3000/flightjs/Flight/-/issues/3 (any issuable widget that is collapsible/expandable)
2. MR Widget: http://gdk.test:3000/flightjs/Flight/-/merge_requests/1
3. Settings block: http://gdk.test:3000/flightjs/Flight/edit

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Related to #512691 (closed)