Fix a string externalisation for i18n

What does this MR do?

EE Port of: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/24514

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• Changelog entry added, if necessary
• Documentation created/updated via this MR
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• Tests added for this feature/bug
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• Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
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