Allow ASM launch if callingUid on top

Fix for
CtsAppTestCases:android.app.cts.AppTaskTests#testStartActivityInTask_NoNewTask.
We would previosuly not allow launches by the top uid for in task starts if
ActivityStarter did not have a source record present as well.

Bug: 288759911
Test: atest AppTaskTest BackgroundActivityLaunchTest
ActivitySecuityModelTest

Change-Id: I0fa72c8b2445d98f909eeeac247f3da9b064df71