[CI] Trigger the alert-test-failed pipeline on the initial comment (e…

…lastic#188909)

## Summary
There was an issue, where after @walterra set up the
[integration](elastic/kibana-operations#160),
and an issue was created
(elastic#188896) there were no
notifications sent to the requested channel.

The cause is probably the initial, [labeling
comment](elastic#188896 (comment))
PR coming from `elasticmachine`.

for more context:
https://elastic.slack.com/archives/C5UDAFZQU/p1721715448357519?thread_ts=1721390987.440079&cid=C5UDAFZQU

.github/workflows/alert-failed-test.yml

@@ -7,7 +7,7 @@ jobs:
     name: Alert on failed test
     if: |
       !github.event.issue.pull_request
-      && github.event.comment.user.login == 'kibanamachine'
+      && (github.event.comment.user.login == 'kibanamachine' || github.event.comment.user.login == 'elasticmachine')
     runs-on: ubuntu-latest
     steps:
       - name: Checkout kibana-operations