Add tests for exception handling for load_json_file()

[JCantu248]

💡 Summary

Add a test case to verify the exception handler in load_json_file()

Motivation and context

This is needed to verify our exception handling code is correct.

Implementation notes

Please provide details for implementation, such as:

Add a test case that passes in a non-existent file and verify the exception is caught in the except block.

Acceptance criteria

Work is finished when a test for the exception handling is added and all pytest cases are successful.

[schmelz21]

Completed in Release 1.0.0.