Resolve "When signup is disabled it is not reflected in the UI"

What does this MR do?

Fixes bug, reported by customer https://gitlab.com/gitlab-org/gitlab-ce/issues/66649 by properly passing "signup enabled" flag to helper

Assuming that signup is disabled in admin >> settings >> general >> signup restrictions

before	after
(Signup is marked green)	(Signup is disabled and has no active link)

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry for user-facing changes, or community contribution. Check the link for other scenarios.
• [-] Documentation created/updated or follow-up review issue created
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• [-] Database guides
• [-] Separation of EE specific content