feat(GlCard): Use color design tokens in GlCard

Closes #2683

See merge request gitlab-org/gitlab-ui!4290



Merged-by: Scott de Jonge <sdejonge@gitlab.com>
Approved-by: Dan MH <dmizzi-harris@gitlab.com>
Approved-by: Scott de Jonge <sdejonge@gitlab.com>
Co-authored-by: GitLab Bot <gitlab-bot@gitlab.com>
Co-authored-by: Thomas Hutterer <thutterer@gitlab.com>

# [85.1.0](gitlab-org/gitlab-ui@v85.0.2...v85.1.0) (2024-06-25)

### Features

* **GlCard:** Use design tokens for colors and border in GlCard ([3ecb2cdd](gitlab-org/gitlab-ui@3ecb2cdd))