ingress-nginx - upgrade the controller to v1.8.4

[crssnd]

What Chart should be upgraded?:

kubernetes-ingress-nginx/ingress-nginx - not sure if we also need to upgrade the chart, but the controller version should be v1.8.4

Check for any possible breaking changes as we will jump a couple of patch releases.

Why should this Chart be upgraded?:

• We need to perform a security upgrade.
• We need it for a new feature: which feature (link to blocked issue).
• We need to keep up to prevent future issues.
• Other: Write the reason here

Acceptance criteria:

• I checked the migration of the new Chart:
  • I upgraded a Chart and determined that no migration steps are needed.
  • I upgraded a Chart and added migration steps.
• I tested the functionality provided by the new Chart (e.g., Auth flow, Grafana dashboards, etc.)