test_in_sensor_zoom.py: Increase RMS diff threshold for cropped RAW image comparison

Some sensors may experience slight offsets caused by OIS while zooming in. This in general
isn't noticeable by the human eye. As a result, we can increase the rms
threshold difference between client software cropped RAW and HAL cropped RAW.

Bug: 315527501

Test: Vendor testing

Change-Id: I90ef8e1fca0e48fa3bd2d226eff6a8a326985414
Signed-off-by: Jayant Chowdhary <jchowdhary@google.com>