Add GROUP viewtype for GroupNotificationViewHolder

Use GROUP viewtype instead of GROUP_COLLAPSED and
GROUP_EXPANDED for GroupNotificationViewHolder.
The state of expanded and collapsed are handled by
GroupNotificationViewHolder instead of being dependent
on the viewtype.

Bug: 231455997
Test: manual - tested on seahawk. Added and modified unit tests.
Change-Id: I60559bf857b5faa154f46c7ea6985ee7655d19d5
10 files changed