[AWS::EKS::Cluster] - [Enhancement] - not able to use KubernetesNetworkConfig.ServiceIpv4Cidr with Fn::GetAtt

### Name of the resource

AWS::EKS::Cluster

### Resource name

AWS::EKS::Cluster

### Description

Currently in cloudformation, users are not available to use serviceIpv4Cidr under Fn::GetAtt.

However it is possible with the use of serviceIpv6Cidr, the only way for customer to get that value is basically using custom resources or using aws cli

### Other Details

_No response_

Start by reviewing the AWS::EKS::Cluster resource and its KubernetesNetworkConfig.ServiceIpv4Cidr attribute, then compare its behavior with ServiceIpv6Cidr under Fn::GetAtt. Done means customers can retrieve ServiceIpv4Cidr through Fn::GetAtt without a custom resource or AWS CLI.

Written by the indexing model from the issue text.