feat: support Terraform execution with and without tfvars in tf-smurf workflow

[kalyani-cd]

Summary

Updated the tf-smurf workflow to support Terraform execution in both scenarios:

• Using a .tfvars file
• Without a .tfvars file

Changes

• Added support for Terraform commands without requiring a tfvars file.
• Retained support for existing workflows that use tfvars.
• Updated the workflow logic to handle both execution paths.

Testing

• Verified Terraform execution with tfvars.
• Verified Terraform execution without tfvars.
• Confirmed existing workflow behavior remains unchanged.