Add GitLab UI UX reviewers

Why is this change being made?

We recently added a custom Danger rule for picking UX reviewers based on the components being modified in GitLab UI: gitlab-org/gitlab-ui@f092cfb3

Some of the UX reviewers in that list aren't marked as reviewers of any project, which seems to be preventing the roulette from matching usernames from the COMPONENT_UX_MAP map to actual user profiles. This MR addresses this by marking the affected users as GitLab UI UX reviewers.

Relevant page in the review app: https://gitlab-ui-ux-reviewers.about.gitlab-review.app/handbook/engineering/projects/index.html#gitlab-ui

Author Checklist

• Provided a concise title for the MR
• Added a description to this MR explaining the reasons for the proposed change, per say-why-not-just-what
• Assign this change to the correct DRI
  • If the change relates to any part of the project other than updates to content and/or data files (e.g. team.yml) please make sure to ping @gl-static-site-editor in a comment for a review and merge.
  • If the DRI for the page/s being updated isn't immediate clear, then assign it to your manager.
  • If your manager does not have merge rights, please ask someone to merge it AFTER it has been approved by your manager in #mr-buddies

For help with failing pipelines reach out in #mr-buddies in Slack