feat(guides): fix connectivity in observability namespace

[Automaat]

We now always add labels with mesh, even if mesh is not specified. Resulting in empty label in policy, for example:

apiVersion: kuma.io/v1alpha1
kind: HostnameGenerator
metadata:
  name: local-mesh-external-service
  namespace: kuma-system
  labels:
    kuma.io/mesh: 

[netlify]

✅ Deploy Preview for kuma ready!

Name	Link
🔨 Latest commit	1bb68ac
🔍 Latest deploy log	https://app.netlify.com/sites/kuma/deploys/6736343e7ca3580008f113ab
😎 Deploy Preview	https://deploy-preview-2088--kuma.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.
Lighthouse	1 paths audited Performance: 92 (🟢 up 1 from production) Accessibility: 90 (no change from production) Best Practices: 100 (no change from production) SEO: 92 (no change from production) PWA: 80 (no change from production) View the detailed breakdown and full score reports

---

To edit notification comments on pull requests, go to your Netlify site configuration.