CameraITS: add log_path to its_session_utils

Details: for validate_lighting, artifacts would be saved to current
working directory. Added an option to specify a log path where artifacts
would be saved instead. Mirrored from cl/479657102.

Bug: 251498064
Test: tested locally on Pixel device.
Change-Id: I4f5daf8196db8766d86a712ef9f071411bf7609f
2 files changed