Camera ITS: Relax threshold used for verifying brightness increase

- Relax img_delta_threshold used for checking for increasing
means to account for partner precision errors.
- Since the asserting means check is for the non-ISO
compensable range, relaxing the threshold is not a
critical check for verifying exposure time priority behavior applicable
in the ISO compensable range.

Test: Camera ITS
Bug: 409090198
Flag: EXEMPT bug fix
Change-Id: I105c98cf7f8944c96ca4422157d9a63e6c36ae1b
1 file changed