Added Slack failure notification to the new Collect engineering metrics job. (#30566)

Fixes #29140

I intended to add a Slack notification but forgot in the previous PR.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Chores**
* Added automated Slack notifications for failed scheduled workflow
runs.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

.github/workflows/collect-eng-metrics.yml

@@ -53,3 +53,24 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           SERVICE_ACCOUNT_KEY_PATH: './service-account-key.json'
+
+      - name: Slack notification
+        if: github.event_name == 'schedule' && failure()
+        uses: slackapi/slack-github-action@e28cf165c92ffef168d23c5c9000cffc8a25e117 # v1.24.0
+        with:
+          payload: |
+            {
+              "text": "${{ job.status }}",
+              "blocks": [
+                {
+                  "type": "section",
+                  "text": {
+                    "type": "mrkdwn",
+                    "text": "Collect engineering metrics result: ${{ job.status }}\nhttps://github.com/fleetdm/fleet/actions/runs/${{  github.run_id }}"
+                  }
+                }
+              ]
+            }
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_G_HELP_ENGINEERING_WEBHOOK_URL }}
+          SLACK_WEBHOOK_TYPE: INCOMING_WEBHOOK