[BUG] can't open notebook 'docs/demo/GCP/mortgage-xgboost4j-gpu-scala.ipynb'

[zhanga5]

Describe the bug
Can't open notebook docs/demo/GCP/mortgage-xgboost4j-gpu-scala.ipynb via Github web UI like others. It encountered error:

Sorry, something went wrong. Reload?

If open via Jupyter Notebook (6.4.5) will encounter error:

Unreadable Notebook: /home/jovyan/work/github.com/nvidia/spark-rapids/docs/demo/GCP/mortgage-xgboost4j-gpu-scala.ipynb NotJSONError('Notebook does not appear to be JSON: \'\\ufeff{\\n "metadata": {\\n "name": "...')

Steps/Code to reproduce bug
Open below link via web browser and will be failed to present the notebook content:
https://github.com/NVIDIA/spark-rapids/blob/branch-21.12/docs/demo/GCP/mortgage-xgboost4j-gpu-scala.ipynb

Expected behavior
Like other notebooks should be able to present content on Github web UI and can be opened via Jupyter Notebook.

Additional context
If upload & open via Jupyter Notebook then different error will be encountered. And it will be fixed automatically after confirmation.

Notebook validation failed: 'display_name' is a required property:
{
 "language": "scala",
 "name": "spark2-scala"
}