Fix for uirendering.cts.testclasses.WideColorGamutTests#testCanvasDrawColorLong

Increase the test threshold to accodomodate floating point precision conversion
differences between old ARM Bifrost GPU(like Mali G-76) and ARM Valhall
GPU(the latest architecture).

Bug: 207402705

Signed-off-by: Rohit Kothari <r.kothari@samsung.com>
Change-Id: Ia3d7c96c093c5464b43d39a818e7aaa6a1f474a1