Support for ipam-ipv4-pool-id annotation in EKS Auto Mode

[flyingpie]

Describe the feature you are requesting
It seems that the alb.ingress.kubernetes.io/ipam-ipv4-pool-id annotation is currently not supported when using EKS in "Auto Mode". I'd love to see that support being added.

Motivation
Being able to have a fixed set of IP addresses assigned to the Application Load Balancer, so we can work with clients that employ IP allow-listing on their firewalls.

Describe the proposed solution you'd like
The same alb.ingress.kubernetes.io/ipam-ipv4-pool-id annotation that's already present on the regular EKS version of the ALB controller, to also work on the EKS Auto Mode version.

Describe alternatives you've considered
Using the regular EKS instead of Auto Mode, though this would add a bunch of extra workload to our process.

I'm not entirely sure if this is the correct place to ask for this, please refer me to the correct place if not.

Contribution Intention (Optional)
-[x] Yes, I am willing to contribute a PR to implement this feature
-[ ] No, I cannot work on a PR at this time

[shuqz]

Hi,
Thank you for reaching out to us. In our documentation we mentioned which attributes are supported by EKS auto mode: https://docs.aws.amazon.com/eks/latest/userguide/auto-configure-alb.html#_considerations

Unfortunately this is not a support we can provide from our side, EKS will decide when to support all of controller's annotation in auto mode.