git: Kill git blame process on task drop (#56890)

We replace these tasks often, so we should clean up after ourselves
here.

Release Notes:

- git: Fix git blame processes not getting dropped properly.
eec06a446aBen Brandt committed on 5/15/2026, 3:53:21 PM· committed by GitHubparentbd725ce
1 file changedLine totals unavailable