ci(CodeQuality): enable eslint-8

What does this MR do?

Activates ESLint 8 on GitLab Code Quality CI to avoid failures after !2709 (merged) (eslint upgrade from 7 to 8).

Closes #1833 (closed)

• Last success job (just before !2709 (merged) merged): https://gitlab.com/gitlab-org/gitlab-ui/-/jobs/2505646289
• First failed job (with !2709 (merged) merged): https://gitlab.com/gitlab-org/gitlab-ui/-/jobs/2511034787
• First success job with this MR: https://gitlab.com/gitlab-org/gitlab-ui/-/jobs/2543562607

MR widget

Does this MR meet the acceptance criteria?

Conformity

• Code review guidelines.
• GitLab UI's contributing guidlines.
• [n/a] If it changes a Pajamas-compliant component's look & feel, the MR has been reviewed by a UX designer.
• [n/a] If it changes GitLab UI's documentation guidelines, the MR has been reviewed by a Technical Writer.
• [n/a] If the MR changes a component's API, integration MR(s) have been opened in the following projects to ensure that the @gitlab/ui package can be upgraded quickly after the changes are released:
  • [n/a] GitLab: mr_url
  • [n/a] CustomersDot: mr_url
  • [n/a] Status Page: mr_url
• [n/a] Added the ~"component:*" label(s) if applicable.

Security

n/a

Accessibility

n/a

Updates !1700 (merged)