Support launching an intent and a task from the same app as multi-instance

Similar to ag/16820166, add FLAG_ACTIVITY_MULTIPLE_TASK to the fillInIntent

Fixes: 222583964
Fixes: 217965464
Fixes: 221415250
Test: https://recall.googleplex.com/projects/f46cfe9c-8076-4efe-bf8a-b1cc4f1f5e1b/sessions/7606236a-3350-49d6-bfad-9e6a609413d1
Change-Id: I676358ef1cbff8317995430de961a0a3242c0cbf