fix: apply runner_group variable when re-registering a runner

[juliannguyen4]

Description

This addresses a bug where runner_group is ignored when re-registering a runner.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• Small minor change not affecting the Ansible Role code (Github Actions Workflow, Documentation etc.)

How Has This Been Tested?

I have a private repo that depends on this role in requirements.yml. I pointed requirements.yml to use my fork's commit, and the bug was resolved.