Increase the contrast ratio of the breadcrumb separator so it exceeds
our target minimum of 3:1

fix(GlBreadcrumb): increase contrast ratio of breadcrumb separator

See merge request gitlab-org/gitlab-ui!4414



Merged-by: Scott de Jonge <sdejonge@gitlab.com>
Approved-by: Scott de Jonge <sdejonge@gitlab.com>
Approved-by: Jeremy Elder <jelder@gitlab.com>
Co-authored-by: GitLab Bot <gitlab-bot@gitlab.com>
Co-authored-by: danmh <dmizzi-harris@gitlab.com>

## [86.14.4](gitlab-org/gitlab-ui@v86.14.3...v86.14.4) (2024-07-23)

### Bug Fixes

* **GlBreadcrumb:** increase contrast ratio of breadcrumb separator ([646a106a](gitlab-org/gitlab-ui@646a106a))