Fix stale ENI comment on the ECS service lifecycle

[ale210]

For #255. Comment-only.

The comment explaining why aws_ecs_service has no create_before_destroy still reasoned about ENI slots on two m5.large hosts. Every task is bridge-mode now and the cluster is one t3a.medium, so the reason is memory: a duplicate service doubles its reservation on a host with about 1 GB to spare. This was the one stale comment left out of #263.

Expected plan: no changes.

[github-actions]

Terraform plan in terraform
With backend config files: terraform/prod.backend.tfvars

No changes. Your infrastructure matches the configuration.

No changes. Your infrastructure matches the configuration.

Terraform has compared your real infrastructure against your configuration
and found no differences, so no changes are needed.

✅ Plan applied in Terraform apply (OIDC) #106