Remove role_tags from cisagov/terraform-state-read-role-tf-module configuration

[jsf9k]

🗣 Description

This pull request modifies the Terraform code to remove role_tags from the cisagov/terraform-state-read-role-tf-module configuration.

💭 Motivation and context

This is in accordance with the changes in cisagov/terraform-state-read-role-tf-module#5.

Note that var.tags (minus the Workspace tag, if present) is passed in via the provider's default tags, so there is no need to use additional_role_tags here.

🧪 Testing

I tested these changes by running a terraform apply against our production COOL environment and noting that the only changes to be made were to add some tags to extant IAM policy resources.

✅ Checklist

• [x] This PR has an informative and human-readable title.
• [x] Changes are limited to a single goal - eschew scope creep!
• [x] All relevant type-of-change labels have been added.
• [x] I have read the CONTRIBUTING document.
• [x] These code changes follow cisagov code standards.
• [x] All new and existing tests pass.