Bug fix: Blank requests

[gnmeyer]

Issue: Terraform PR Job Fails When No Changes Are Detected

Description

When a Terraform plan results in no changes, the PR job fails with the following error:

RequestError [HttpError]: Validation Failed: {"resource":"IssueComment","code":"unprocessable","field":"data","message":"Body cannot be blank"}

This happens because the terraform-change-pr-commenter action attempts to post an empty comment to the PR, which is not allowed by the GitHub API.

Steps to Reproduce

1. Push a blank main.tf file to trigger a Terraform plan.

2. Terraform detects no infrastructure changes and outputs:

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