Fix clipTopAmount when read in 2 more critical places

* When determining the size of the rectangle made available for the a11y services (e.g. talkback)
* When determining which child view is being touched by our custom logic

Test: reproduce the bug, then navigate the screen with talkback; notice that the rectangle is correctly sized
Bug: 230080345
Change-Id: I01293c0aecbeee559e97f348ff7c4151a64538ab