Mark group summaries as interrupted when group alert transfer happens

When the group summary should heads up but the alert is transferred to a child, we want to avoid incorrectly re-alerting on the group on a ranking update because it looks like the group is in a "should alert, hasn't alerted yet" state.

Bug: 248325248
Bug: 254472116
Test: HeadsUpCoordinatorTest, manually verified group HUNs seem to behave OK
Change-Id: Ia4ada5eeb6abf137b4e16a486d8c7c6152bc57d2