roll: recipes_version.txt post_attribution_roller_retrigger: Fix hash extraction

Prior to http://fxrev.dev/1455951 this recipe was able to access the
most recently passing commit hash as
"status['newest_passing']['commit']". That change added information to
the output properties and now it's accessible as
"status['newest_passing']['commit']['hash']". Update the recipe to
correctly access the hash.

Original-Bug: b/467991156
Original-Reviewed-on: https://pigweed-review.googlesource.com/c/infra/recipes/+/364352
Presubmit-Verified: CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com>
Original-Revision: b6f296b5f6d4d0fe3628e06973bd6d4a8d7bdb79
GitOrigin-RevId: 5ee6925e69666b6a610902604a8606a2d813b120
Change-Id: Ib023d65ca5e3f5778e9d69d1760b35fd9ca0623c