[Task] Remove support for EKS 1.23
Description
As per the calendar for Amazon EKS end of support 11 Oct 2024 is the extended end of support for Kubernetes version 1.23 See https://endoflife.date/amazon-eks
We need to remove support for 1.23 and modify any relevant docs wherever possible. Reference PR - see here
/assign. Will pick it up when the time comes. Let me know if are we waiting for AWS to announce the exact date or if it is something related to Eksctl's internal schedule.
Since after this change we'll only support EKS 1.24 and upwards, we also need to remove any logic related to dockershim deprecation.
References (i.e. some code areas that need to account for this change):
https://github.com/eksctl-io/eksctl/blob/02c41d5422e587cb7873eb8081084ce8880a7cc4/userdocs/src/usage/container-runtime.md?plain=1#L3-L6
https://github.com/eksctl-io/eksctl/blob/02c41d5422e587cb7873eb8081084ce8880a7cc4/pkg/apis/eksctl.io/v1alpha5/defaults.go#L260-L282
https://github.com/eksctl-io/eksctl/blob/02c41d5422e587cb7873eb8081084ce8880a7cc4/pkg/apis/eksctl.io/v1alpha5/validation.go#L916-L935
@sbdtu5498 I'm removing the good first issue label as removing support for 1.23 involves these ⬆️ specific changes.