Fix launching ActivityGroup with ActivityEmbedding

ActivityGroup has been deprecated since Android H, but there are still
apps using it. When it is used, the child Activity will not have its own
corresponding ActivityRecord. If we treat it as normal Activity, there
will be issue because we can't find Task with its token, nor reparent it
with its token.

Skip child Activity (the one launched in ActivityGroup) for any
lifecycle event.

Fix: 256533615
Test: manually verify
Change-Id: Ibccf1575c3b229a0912f843f6468a6c3e24a893f