Update FileAttachment.objects.create_from_filediff to set needed fields.
Review Request #13532 — Created Feb. 12, 2024 and submitted — Latest diff uploaded
It turns out that having a FileAttachment for a diff that does not have
the review request set will cause the review UI instantiation to fail.
This change fixes thecreate_from_filediffmethod to set the review
request and local site fields correctly based on the given FileDiff's
review request.
- Ran unit tests.
- Used this when automatically creating a diff file attachment in a
later change.