A few updates to task views to enable shell transitions on auto.

- Call base.onTaskView as part of prepareOpenAnimation as that is
  effectively when the task in taskview appears now
- Add a new method startRootTask(); to start an already create root task
  inside the task view. It uses prepareOpenAnimatino() but without the
  start and finish transition surface-controls
- Add a new method to reorderTaskViewTask via shell transitions and also
  add support for reorder as part of setTaskViewVisible.

Bug: 333096229
Test: <pending>
Change-Id: I906a080095870131d721f8a5365c80c7a5350d1f