Update the task stack state when resizing the tasks after the PiP animation

- When the animation into PiP ends, we clear the task stack state and
  request a layout prior to resizing the the stack to update the task
  bounds to the stack bounds. This triggers a relayout from the client,
  which fetches the new configuration prior to handling the PiP mode/config
  change scheduled as a part of the PiP mode change.

  We can instead update the task stack state when we resize the tasks to
  ensure that we don't relayout multiple times.

Bug: 75995355
Test: atest CtsActivityManagerDeviceTestCases:ActivityManagerPinnedStackTests


Change-Id: I58a6e30651f16b85ec160e977554b8d091b461ec