Refactor choose lock password scrolling

Replace the negative margin + inset background hack with a overriding
call to requestRectangleOnScreen, which will also make a best effort
to show all the password requirements if there are multiple of them.

Bug: 38236574
Test: Added ScrollToParentEditTextTest
Change-Id: Id570652b64434b2d0b25c231540375d93884aaa9