Fix `/repos/{owner}/{repo}/pulls/{index}/files` endpoint not populating `previous_fil...

Fix `/repos/{owner}/{repo}/pulls/{index}/files` endpoint not populating `previous_filename` (#32017) (#32028)

Backport #32017 by @charles-plutohealth

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`status == "rename"` should have read `status == "renamed"`. The typo
means that file.PreviousFilename would never be populated, which e.g.
breaks usage of the Github Action at
https://github.com/dorny/paths-filter.

Co-authored-by: charles-plutohealth <143208583+charles-plutohealth@users.noreply.github.com>