Added slack failure notifications to bespoke environment changes (#4624)

* Added slack failure notifications to apply steps

* pruned failure messages to just preprod/prod apply runs

.github/workflows/terraform-member-environment.yml

@@ -261,6 +261,16 @@ jobs:
             unset workspace
           done
 
+      - name: Slack failure notification
+        uses: slackapi/slack-github-action@e28cf165c92ffef168d23c5c9000cffc8a25e117 # v1.24.0
+        with:
+          payload: |
+            {"blocks":[{"type": "section","text": {"type": "mrkdwn","text": ":no_entry: Failed GitHub Action:"}},{"type": "section","fields":[{"type": "mrkdwn","text": "*Workflow:*\n<${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}|${{ github.workflow }}>"},{"type": "mrkdwn","text": "*Job:*\n${{ github.job }}"},{"type": "mrkdwn","text": "*Repo:*\n${{ github.repository }}"}]}]}
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
+          SLACK_WEBHOOK_TYPE: INCOMING_WEBHOOK
+        if: ${{ failure() }}
+
       - name: Mark job skipped
         if: ${{ steps.workspace.outputs.skip_plan == 'true' }}
         run: |