[2/n] Send Transition when setRequestOrientation()

When setRequestOrientation is invoked we generate a Transition to notify that the activity
might be letterboxed. This happens if ActivityRcord#handlesOrientationChangeFromDescendant()
return false which means that no parent will be interested in the orientation change and so
the normal transition won't be triggered. In case handlesOrientationChangeFromDescendant()
returns true, the Transition won't be triggered because the one related to the rotation
will be generated.

Flag: com.android.window.flags.enable_transition_on_activity_set_requested_orientation
Bug: 409043134
Test: PreSubmit

Change-Id: I57fbebe596bc87fbe0b80a500a37349848369661