fix: add proxy timeout annotations to CMS ingress

Add nginx.ingress.kubernetes.io/proxy-read-timeout: 3600
and proxy-send-timeout: 3600 to prevent 504 Gateway Timeout
on gRPC-Web requests through the nginx ingress controller.

k8s/staging/cms-deployment.yaml

@@ -110,6 +110,8 @@ metadata:
     kubernetes.io/ingress.class: "nginx"
     cert-manager.io/cluster-issuer: "letsencrypt-prod"
     nginx.ingress.kubernetes.io/ssl-redirect: "true"
+    nginx.ingress.kubernetes.io/proxy-read-timeout: "3600"
+    nginx.ingress.kubernetes.io/proxy-send-timeout: "3600"
 spec:
   tls:
   - hosts: