Fix area rendered by ScrollCaptureViewSupport

When rendering the requested image, the updated scrollDelta was not
being accounted for, resulting in rendering the wrong vertical
position. This would happen if the view scrolled as a result of the
request.

Also adds a call invalidate() on the target view after scrolling to
ensure that DisplayLists are correctly rebuilt when rendered here
since there is no synchronization with the render thread.

Test: atest ScrollViewCaptureHelperTest
Change-Id: I1e6aec8dd4352b4ae610657537581689a04b725b