Update ScreenCapture API in response to API council feedback.

Bug: 428924821
Bug: 370855681
Flag: com.android.graphics.surfaceflinger.flags.readback_screenshot
Test: atest CtsWindowManagerDeviceOther:android.server.wm.other.ScreenCaptureTest
Change-Id: I64febff90d2bef8a119d2702527a3fb1d9db2a00