Re-use setRepoResults instead of having a setReposResult message

[charisk]

In #3503 I introduced a new message when I could have just re-used the existing message 🤦 this fixes that.

The setRepoResults message can be re-used because its handling replaces any existing repo results.

I still find the names of messages a bit confusing so that can be tidied up in a separate PR.

Checklist

N/A:

• CHANGELOG.md has been updated to incorporate all user visible changes made by this pull request.
• Issues have been created for any UI or other user-facing changes made by this pull request.
• [Maintainers only] If this pull request makes user-facing changes that require documentation changes, open a corresponding docs pull request in the github/codeql repo and add the ready-for-doc-review label there.