Fix broken UI by setting FinishedAt again
Created by: mrnugget
This was a left-in "debug removal" that I added in https://github.com/sourcegraph/src-cli/commit/348c49a24dc18e6da5a8a231fea52d840ddcc0a3#diff-e7d4e9760b2767b61760170f3620004882b9fa493251c3619f15d68534891e75L142
It broke the UI. I'll release a new version right after merging this.