feat(EmptyState): Invert empty state illustrations in dark mode

mentioned in commit 21391135

mentioned in merge request gitlab!82590 (closed)

mentioned in merge request gitlab-org/gitlab-services/design.gitlab.com!2746 (closed)

mentioned in merge request status-page!474 (merged)

mentioned in merge request gitlab!83216 (merged)

mentioned in merge request gitlab-org/gitlab-services/design.gitlab.com!2755 (merged)

mentioned in merge request gitlab-docs!2518 (merged)

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mentioned in merge request gitlab-docs!2520 (closed)