[P1] Invalid launch template in Terraform when not using custom AMI

[willroberts]

Summary

We may have a bug in the ECS Terraform module where launch templates are created. When not using a custom AMI, terraform apply can fail with the following error:

ValidationError: You must use a valid fully-formed launch template. The request must contain the parameter ImageId

Impacted services

• [ ] The frontend app
• [ ] The game servers
• [ ] Game builds or automation scripts
• [ ] Tests or Github Actions
• [x] Infrastructure (Terraform)

Steps to reproduce

1. Configure a TF environment to use a standard ECS AMI instead of a custom AMI
2. Run terraform apply