Follow-up: Replace SCSS class with gitlab-ui util

The following discussion from !144907 (merged) should be addressed:

• @ekigbo started a discussion: (+1 comment)

  note: It looks like we have both the gl-sm-display-grid and gl-md-display-grid classes, so we should probably add gl-lg-display-grid to gitlab-ui and replace this.

  But that can be a follow-up