Update gitlab-ui to new major version
Follow up to: !2439 (closed).
This one updates gitlab-ui
to latest version: https://gitlab.com/gitlab-org/gitlab-ui.
The only instance in the code of a source import I could find (that would be affected by: https://gitlab.com/gitlab-org/gitlab-ui/-/blob/main/CHANGELOG.md#3600-2022-02-07) was: https://gitlab.com/gitlab-org/gitlab-docs/-/blob/fe3dc6be3debcfc3bbca7ba64f630ba920f9362f/content/frontend/default/components/navigation_toggle.vue#L2. It looks ok already.
This looks ok also: https://gitlab.com/gitlab-org/gitlab-docs/-/blob/fe3dc6be3debcfc3bbca7ba64f630ba920f9362f/content/frontend/404/components/error_message.vue#L2.