Add copyright check
Sample execution:
https://github.com/NVIDIA/NeMo/actions/runs/11563980809/job/32188323290?pr=11048
 Sample execution (with more files with issues prior to change): https://github.com/NVIDIA/NeMo/actions/runs/11528195110/job/32094993197?pr=11048 After copyright notices were added, the copyright check rightfully passes
https://github.com/NVIDIA/NeMo/actions/runs/11564887593/job/32190934995?pr=11048 Changes do not affect CI , so wont run CI
Add copyright check

Sample execution #1 (expected to fail):
https://github.com/NVIDIA/NeMo/actions/runs/11563980809/job/32188323290?pr=11048


Sample execution (with more files with issues prior to change)  #2 (expected to fail): https://github.com/NVIDIA/NeMo/actions/runs/11528195110/job/32094993197?pr=11048


After copyright notices were added, the copyright check rightfully passes
https://github.com/NVIDIA/NeMo/actions/runs/11564887593/job/32190934995?pr=11048