OCPBUGS-35480:updates prerequisites for OVN-K migration

Author: JoeAldinger

modules/nw-ovn-kubernetes-migration.adoc

@@ -25,6 +25,7 @@ Perform the migration only when an interruption in service is acceptable.
 * A reboot can be triggered manually for each node.
 * The cluster is in a known good state, without any errors.
 * Before migration to OVN-Kubernetes, a security group rule must be in place to allow UDP packets on port `6081` for all nodes on all cloud platforms.
+* Before migration to OVN-Kubernetes, set all timeouts for webhooks to 3 seconds or remove them.
 
 .Procedure