FixBug: Round corner gone when scroll to non-first item and drag to close

Add some notification and scroll to non-first item,
Then drag to close notification panel, the top round corner will become
rectangle corner.

Case 1: the round corner only in first item.
Case 2: the round corner cross first and second.

Bug: 80110795
Test: add notifications, scroll, drag to close
Test: atest SystemUITest
Change-Id: I64146ebd1e3b7d19fd5b466290fc9fd5de5b8d5d
1 file changed