Removed logic that sized the view before the shelf

Since the shelf is positioned algorithmically, it can
simply clip the view instead of forcing the height.
This leads to less artificatial animations and avoids
flickers that may happen if the height isn't correct.

Bug: 172289889
Test: expand shade with notifications, observe normal clipping, no hole
Change-Id: I8efae53ba934cdf8553812c513f2de0cc23e1d6c