Fix open ActivityEmbedding split with Shell transition

1. Collect the TaskFragment when reparenting an activity into it.
2. Check adjacent TaskFragment for transition flag FLAG_TRANSLUCENT.
3. Offset the relative position for default animation.

Bug: 207070762
Test: pass existing
Change-Id: I62b533dbb087007e3ef126170691a59929eb75e1
6 files changed