Expand the clip path for bundle groups

 If the NotificationChildrenContainer is a bundle, then the clip path needs to
  be expanded otherwise the summary children will be clipped when translated.
 Expand clip path by the maximum translation of the group summary children

Flag: EXEMPT bugfix

Test: atest NotificationChildrenContainerTest

Bug: 439899631
Change-Id: Id4aa84d122eedff9415d2ca3b1efac17d937d854