Fix flaky/broken test

I think relying on actual CommandQueue is where the flakiness
is coming from so instead I'm calling the callback directly.

Bug: 191264972
Bug: 192356466
Test: atest LaunchConversationActivityTest -c --iterations 20
Change-Id: I23dff9da2b86772a959f144a035b3e884489ea43
1 file changed