InputTests: Disable the white balance adjustments

The display white balance setting seems to impact VirtualDisplays, and
the color filter will show up in the VirtualDisplay screenshots.

Disable the setting hermetically to avoid its impact to the test suite.

Bug: 402659234
Test: Presubmit
Flag: TEST_ONLY
Change-Id: I0ade9e9771671fc2c305caf4718f47c2ecb59908