This commit fixes an UI inconsitency where the arrow did not animate in
sync with with the card's expansion panel during the expansion process.
The solution implemented involves the use of actual DOM element for the
arrow, rather than a pseude-element, allowing for unified animation with
the expansion panel.
Changes:
- Extraction of the expansion arrow into its own Vue component,
`CardExpansionArrow`, improving maintainability and separation of
concerns.
- Transition to using a real DOM element for the expansion arrow, moving
away from the `&:before` pseudo-class. This leads to simpler codebase,
better separation of concerns and closer alignment with HTML
semantics.
