ITS: add Y save to write_uint8_image

Files affected:
  image_processing_utils.py
  opencv_processing_utils.py

Bug: 403575549
Flag: TEST_ONLY
Testing: unit-tests, code search to determine save_rgb_uint_image() usage.
Change-Id: I27efb536310c12ef0db2400487603437d9e21680
2 files changed