Fixes T12097. In D16413, I simplified this code but caused us to load the commit's projects instead of the repository's projects, which is incorrect.

Normally, commits don't have any project tags when Herald evaluates, so using the commit's projects is generally meaningless.

• Tagged a repository with #X.
• Created a Herald object rule for commits with #X as the object ("Always ... do nothing.")
• Ran a commit from the repository.
• Before patch: rule failed to evaluate.
• After patch: rule evaluated and passed.