Adapt missing networkInterfaceSelector in the LoadbalancerSpec of Loadbalancer Object

[Rohit-0505]

Currently, the Loadbalancer object is missing the networkInterfaceSelector field in LoadbalancerSpec. This omission leads to unintended behavior when a Loadbalancer is created by the cloud provider:

• When a Loadbalancer is first created without networkInterfaceSelector, it automatically selects all network interfaces within the associated network.

• This results in a loadbalancerRouting configuration that includes destinations for all networkInterfaces.

• If any networkInterface is later deleted, the loadbalancerRouting destinations become inconsistent, potentially leading to unexpected routing issues.

To prevent these issues, we need to introduce the networkInterfaceSelector field in LoadbalancerSpec.

Proposed changes:

As per Ironcore API design, the Loadbalancerspec must have a networkInterfaceSelector to ensure the loadbalancing across the selected networkInterfaces.

• Add networkInterfaceSelector field in LoadbalancerSpec while creating the LoadBalancer object, and choose the appropriate label for nic in the cloud-provider-ironcore

Ensure below validations via testcases

• Ensure that loadbalancerRouting destinations update correctly when networkIinterfaces are deleted or modified.
• Add Test validation and error handling to prevent inconsistent loadbalancerRouting.