TFENV_TERRAFORM_VERSION not working

[chris-peterson]

Describe the bug
Starting in 3.2.11, terraform environment variables (e.g. TFENV_TERRAFORM_VERSION) aren't working as expected.

To Reproduce

export TFENV_TERRAFORM_VERSION='1.7.5'
make build

With version 3.2.10 and earlier:

./build/tenv tf detect
Resolved version from TFENV_TERRAFORM_VERSION : 1.7.5
Auto-install is disabled. To install Terraform version 1.7.5, you can set environment variable TENV_AUTO_INSTALL=true, or install it via any of the following command: 'tenv terraform install', 'tenv terraform install 1.7.5'
no compatible version found locally
Terraform 1.7.5 will be run from this directory.

With 3.2.11 and later:

./build/tenv tf detect
No version files found for Terraform, fallback to latest-allowed strategy
Scan project to find IAC files
No Terraform version requirement found in project files, fallback to latest strategy
Found compatible version installed locally : 1.10.5
Terraform 1.10.5 will be run from this directory.

Expected behavior
Expected resolved version to be 1.7.5, not 1.10.5

Additional Details
This was introduced in 439b6d9. The prior sha (4fe5463) works as expected