Camera: Fix test pattern data propagation

For sensor muting, the original test pattern data needs to be kept
with the capture request, in case it is overridden by sensor muting mode.

Unfortunately, the copy used the wrong source data entry
(the test pattern mode), resulting in corrupted test pattern data.

Fix that, and also skip the test pattern override entirely when
sensor mute isn't supported. And clean up some unnecessary cast for
clarity.

Test:
  - TestingCamera2 with test patch shows correct color
    for TEST_PATTERN_MODE_SOLID_COLOR,
  - atest CtsCameraTestCases passes
Bug: 173154486
Change-Id: Ib266440eb97476d52a1a48f135464da6cd827004