ATMS: fix the NPE problem in case the dream activity fails to start.

When start the dream activity：
Firstly, the activityrecord of the dream activity is first created in the executeRequest method, and the task of the activityrecord is empty at this time.
Secondly, the startActivityInner method is called to create or get the task, but before calling the setNewTask method, there may be some startup failures, so the task of the activityrecord is still empty at this time.
Finally, our solution is to determine the result of launching the activity.

Test: OEM monkey test
Flag: EXEMPT bugfix
Bug: 381804032
Change-Id: Id7b78f2403580d752609b43fcb24a084b8a91818