In [31114], `get_permalink()` was modified to prevent pretty permalinks from
being generated for posts with the 'future' post status. This inadvertently
broke the pretty permalink preview for scheduled posts. The fix is to include
the 'future' status in the list of statuses that `get_sample_permalink()` fakes
as 'publish' before it fetches a permalink.
Props DrewAPicture.
Fixes#30910.
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