Don't merge task view transitions in UnfoldTransitionHandler

For TRANSIT_CHANGE TaskViewTransitions needs to do some work (i.e.
reparent the surface & set the position), however, this was being
skipped because the transition was getting merged with the unfold
transition. Skipping the merge allows TaskViewTransitions to apply
these changes in the transition & resolves this issue.

Bug: 286549869
Test: manual - expand a bubble on a folded device
             - unfold the device
             => observe that the bubble remains expanded and the
                content is in the correct position and bounds
Change-Id: I402a47f72510045840715a6583ff3614228e39a3