feat(css): Added gl-w-grid-size-28 utility class

mentioned in commit 049f9820

mentioned in merge request gitlab!78540 (merged)

mentioned in merge request gitlab-org/gitlab-services/design.gitlab.com!2690 (closed)

mentioned in merge request status-page!450 (merged)

mentioned in merge request gitlab-org/gitlab-services/design.gitlab.com!2698 (merged)

mentioned in merge request gitlab-docs!2384 (merged)

mentioned in merge request gitlab-docs!2385 (merged)