Include ActivityRecord in the transition when windowingMode changed

When Shell start transition with changing windowing mode on Task, it
may only collect the Task as a transition participant. We want to also
include ActivityRecord so that when the transition is finished, it will
dispatch app transition finished event correctly.

Fix: 221185010
Test: atest WmTests:ActivityRecordTests
      #testShellTransitionTaskWindowingModeChange
Change-Id: Ib59b83600b803bd6e96ed7b0db1089b7c3da21bd