chore(ci): Identify which repository the flakes are reported for (#2824)

## Description

<!-- A summary of what this pull request achieves and a rough list of
changes. -->
Just prefixes the discord message with the repository name. See [this
msg](https://discord.com/channels/949724860232392765/1194275793220665375/1298560426392555601)
generated from this PR.

## Change checklist

- [x] Self-review.
- ~~[ ] Documentation updates following the [style
guide](https://rust-lang.github.io/rfcs/1574-more-api-documentation-conventions.html#appendix-a-full-conventions-text),
if relevant.~~
- ~~[ ] Tests if relevant.~~
- ~~[ ] All breaking changes documented.~~

.github/workflows/flaky.yaml

@@ -93,6 +93,7 @@ jobs:
         uses: n0-computer/discord-webhook-notify@v1
         if: ${{ env.TESTS_RESULT == 'failure' || env.TESTS_RESULT == 'success' }}
         with:
+          text: "Flaky tests in **${{ github.repository }}**:"
           severity: ${{ env.TESTS_RESULT == 'failure' && 'warn' || 'info' }}
           details: ${{ env.TESTS_RESULT == 'failure' && steps.make_summary.outputs.summary || 'No flaky failures!' }}
           webhookUrl: ${{ secrets.DISCORD_N0_GITHUB_CHANNEL_WEBHOOK_URL }}