ci: Send doc URL check result to #mission-docs (no-changelog) (#7981)

## Summary
Provide details about your pull request and what it adds, fixes, or
changes. Photos and videos are recommended.
https://n8nio.slack.com/archives/C0350564QTG/p1702284519394179
...

#### How to test the change:
1. ...


## Issues fixed
Include links to Github issue or Community forum post or **Linear
ticket**:
> Important in order to close automatically and provide context to
reviewers

...


## Review / Merge checklist
- [ ] PR title and summary are descriptive. **Remember, the title
automatically goes into the changelog. Use `(no-changelog)` otherwise.**
([conventions](https://github.com/n8n-io/n8n/blob/master/.github/pull_request_title_conventions.md))
- [ ] [Docs updated](https://github.com/n8n-io/n8n-docs) or follow-up
ticket created.
- [ ] Tests included.
> A bug is not considered fixed, unless a test is added to prevent it
from happening again. A feature is not complete without tests.
  >
> *(internal)* You can use Slack commands to trigger [e2e
tests](https://www.notion.so/n8n/How-to-use-Test-Instances-d65f49dfc51f441ea44367fb6f67eb0a?pvs=4#a39f9e5ba64a48b58a71d81c837e8227)
or [deploy test
instance](https://www.notion.so/n8n/How-to-use-Test-Instances-d65f49dfc51f441ea44367fb6f67eb0a?pvs=4#f6a177d32bde4b57ae2da0b8e454bfce)
or [deploy early access version on
Cloud](https://www.notion.so/n8n/Cloudbot-3dbe779836004972b7057bc989526998?pvs=4#fef2d36ab02247e1a0f65a74f6fb534e).

.github/workflows/check-documentation-urls.yml

@@ -29,7 +29,7 @@ jobs:
       - name: Build nodes-base
         run: pnpm --filter @n8n/client-oauth2 --filter n8n-workflow --filter n8n-core --filter n8n-nodes-base build
 
-      - name: Test URLS
+      - name: Test URLs
         run: node scripts/validate-docs-links.js
 
       - name: Notify Slack on failure
@@ -37,6 +37,6 @@ jobs:
         if: failure()
         with:
           status: ${{ job.status }}
-          channel: '#alerts-build'
+          channel: '#mission-docs'
           webhook-url: ${{ secrets.SLACK_WEBHOOK_URL }}
           message: Documentation URLs check failed (${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }})