Add slack notification if testing fails in main (#10763)

Author: hamishfagg

.github/workflows/build_deploy_staging.yml

@@ -74,4 +74,53 @@ jobs:
       group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}-tests
       cancel-in-progress: true
     uses: ./.github/workflows/test_on_deploy.yml
-    secrets: inherit
+    secrets: inherit
+  
+  slack_message:
+    if: always()
+    name: Notify Slack
+    needs: [run_tests]
+    runs-on: mdb-dev
+    steps:
+      - name: Notify of failing tests
+        if: needs.run_tests.result == 'failure'
+        uses: slackapi/slack-github-action@v1.26.0
+        with:
+          channel-id: ${{ secrets.SLACK_DEPLOYMENTS_CHANNEL_ID }}
+          payload: |
+            {
+              "attachments": [
+                {
+                  "color": "#FF4444",
+                  "blocks": [
+                    {
+                      "type": "header",
+                      "text": {
+                        "type": "plain_text",
+                        "text": "TEST RUN FAILED ON MAIN",
+                        "emoji": true
+                      }
+                    },
+                    {
+                      "type": "section",
+                      "text": {
+                        "type": "mrkdwn",
+                        "text": " "
+                      },
+                      "fields": [
+                        {
+                          "type": "mrkdwn",
+                          "text": "*Commit*\n<${{ github.server_url }}/${{ github.repository }}/commit/${{ github.sha }}|${{ github.sha }}>"
+                        },
+                        {
+                          "type": "mrkdwn",
+                          "text": "*Workflow Run*\n<${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}|${{ github.workflow }}>"
+                        }
+                      ]
+                    }
+                  ]
+                }
+              ]
+            }
+        env:
+          SLACK_BOT_TOKEN: ${{ secrets.GH_ACTIONS_SLACK_BOT_TOKEN }}