[AE] Fix focus due to explicitly setting adjacent activity resumed

The focused app was incorrectly set to the adjacent activity of the
top-resumed activity, causing the top-resumed activity to not get
the focus.

Bug: 348307146
Test: atest TaskFragmentTest
Flag: EXEMPT bugfix
Change-Id: Icd2fff7f0c136a2ef667eb3aa51138f1f95ed313