Iac Engines not used for dependency blocks

[partcyborg]

Describe the bug

If a terragrunt module is configured to use Iac Engines, the engine is not used when that module's output is read via a dependency block

Steps To Reproduce

• Configure 2 terragrunt modules, both of which have an engine block
• Make module 2 a dependency of module 1
• Run terragrunt plan for module 2

Expected behavior

When terragrunt process the dependency on module 1, the terraform output -json command should be executed using the IaC engine.

Versions

• Terragrunt version: v0.75.0
• Engine source: https://github.com/gruntwork-io/terragrunt-engine-go/tree/main/examples/client-server (with a small change to use non-relative paths)
• Engine version: main branch
• Environment details (Ubuntu 20.04, Windows 10, etc.): Ubuntu 24.04

Additional context

See #3962 for more details