[3] Upgrade OPA gatekeeper to v3.13.4

[lucianvlad]

What Chart should be upgraded?:

upstream / open-policy-agent-gatekeeper https://github.com/open-policy-agent/gatekeeper/releases/tag/v3.13.4 Or to v3.14.0

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).
• [x] 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.)