Group new free notis if autogroup summary exists

In the case where an app posted enough notifications to
get an autogrpup summary, but then canceled most of them,
add all new group-less notifications to the autogroup summary
even if the total number of notifications currently posted
by the app is < the autogroup trigger number

Test: runtest systemui-notification, cts
Change-Id: I6f7a8a0140abcff2b0f78eacfbf23cfab12897fa
Fixes: 64158706