Remove useIdentityTransform from DisplayCaptureArgs.

Screenshots do not set useIdentityTransfrom to true with
a rotated display. The default value is false in
SurfaceFlinger and is not relevant for captureLayers,
which is the API that will be used for screenshots going
forward. Rotation flags are no longer relevant in
DisplayRenderArea and rotation values can be simplified
to 0 rotation by default.

Bug: 293445881
Test: atest LayerStateTest
Test: presubmit
Change-Id: Id0cce05458c3daa4078097057f00fd856df1e092