set webhook failurePolicy to Ignore

Prevents namespace operations from being hard-blocked when the
webhook pod is unavailable (e.g. during install/upgrade/restart).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: obezpalko

charts/namespace-admission/templates/webhook.yaml

@@ -22,3 +22,4 @@ webhooks:
     admissionReviewVersions: ["v1"]
     sideEffects: "None"
     timeoutSeconds: 10
+    failurePolicy: Ignore