[release-v1.35] Clarify listener-network annotation support (#1064)

* Clarify listener-network annotation support

Updated the listener-network annotation description to indicate it is not supported.

* Remove unsupported listener network annotation

* Update comment on listener network annotation

---------

Co-authored-by: Björn Fischer <bjoern.fischer@stackit.cloud>

Author: stackit-ske

docs/load-balancer.md

@@ -49,7 +49,6 @@ Values for boolean annotations are parsed according to [ParseBool](https://pkg.g
 | lb.stackit.cloud/service-plan-id                    | p10        | Defines the [plan ID](https://docs.api.eu01.stackit.cloud/documentation/load-balancer/version/v1#tag/Load-Balancer/operation/APIService_CreateLoadBalancer) when creating a load balancer. Allowed values are: p10, p50, p250 and p750                                                                                                                                                                                   |
 | lb.stackit.cloud/ip-mode-proxy                      | false      | If true, the load balancer will be reported to Kubernetes as a proxy (in the service status). This causes connections to the load balancer IP that come from within the cluster to be routed to through the load balancer, rather than directly to the `kube-proxy`. Requires Kubernetes v1.30. The annotation has no effect on earlier versions. Recommended in combination with the TCP proxy protocol.                |
 | lb.stackit.cloud/session-persistence-with-source-ip | false      | When set to true, all connections from the same source IP are consistently routed to the same target. This setting changes the load balancing algorithm to Maglev. Note, this only works reliably when `externalTrafficPolicy: Local` is set on the Service, and each node has exactly one backing pod. Otherwise, session persistence may break.                                                                        |
-| lb.stackit.cloud/listener-network                   | _none_     | When set, defines the network in which the load balancer should listen. If not set, the SKE network is used for listening. The value must be a network ID, not a subnet. The annotation can neither be changed nor be added or removed after service creation.                                                                                                                                                           |
 
 ### Supported yawol Annotations
 

pkg/ccm/loadbalancer_spec.go

@@ -52,6 +52,7 @@ const (
 	// If not set, the SKE network is used for listening.
 	// The value must be a network ID, not a subnet.
 	// The annotation can neither be changed nor be added or removed after service creation.
+	// This annotation is currently not supported by STACKIT and only works in very specific circumstances.
 	listenerNetworkAnnotation = "lb.stackit.cloud/listener-network"
 )