Should the bottlerocket containerd-config.toml file have discard_unpacked_layers set to true by default

**What I'd like:** discard_unpacked_layers to be enabled for containerd by default.

Please see [this issue](https://github.com/awslabs/amazon-eks-ami/issues/1359) in the default EKS AMI for full details and testing done in that AMI that should apply to Bottlerocket too.

I believe the containerd settings are [here](https://github.com/bottlerocket-os/bottlerocket/blob/develop/packages/containerd/containerd-config-toml_k8s_containerd_sock) for the default version and [here](https://github.com/bottlerocket-os/bottlerocket/blob/develop/packages/containerd/containerd-config-toml_k8s_nvidia_containerd_sock) for nvidia version.

**Any alternatives you've considered:** This would require making a custom AMI as described in [this issue](https://github.com/bottlerocket-os/bottlerocket/issues/2408).