Add mechanism to request Core to reparent to the TDA on launch

- This mirrors WCT#setReparentLeafTaskToTda(), which is necessary when
  a task is in a root task, but needs to be reparented to the TDA on
  activity start

Bug: 396313972
Flag: EXEMPT bugfix
Test: TBD
Change-Id: I196b19bad854fb3eeefca951a8f994ef6f2313f1