BUG: Related posts don't show up on new blog posts

[beechnut]

Earlier today, we merged #4076.

Expected behavior: display three related posts at the bottom of the new post

Actual behavior: empty related posts area

[michelle-rago]

@beechnut Seems that the related posts aren't showing up on https://18f.gsa.gov/2024/11/05/three-ways-to-write-fearless-spreadsheet-formulas/ and beyond. Adding this here in case it helps debug.