Forcibly recalculate size of the notification expanded view.

This helps avoid a race condition that can sometimes leave
the status bar handle untouchable (read: hiding behind the
expanded view's transparent window, which is too large
because the close handle's height has not yet been
calculated) on first boot.

Bug: 5122306
Change-Id: I5fa2595798a66289c2c33d7c78dd16f9db066ede