Don't claim doze or brightness capabilities

and return unsupported in Display::setDisplayBrighness
... as getDozeSupport() and getDisplayBrightnessSupport()
both return false and mention being unimplemented.

Bug: b/130079341
Bug: b/150057963
Test: vts -m VtsHalGraphicsComposerV2_3TargetTest
Change-Id: Ia085db225d20df1d139127d092e0d32b565020f4