Remove permission token from startActivityAsCaller

The call is protected by the signature permission
START_ACTIVITY_AS_CALLER. This will remove the need for additional data
to be passed from system server.

Bug: 222082547
Bug: 226354782
Test: atest ActivityTaskManagerServiceTests, atest ChooserActivityTest,
      manual testing
Change-Id: I94f34a68e390569ec14dfebb1902a7c30558864f