Wait for app launch animation to complete after launching apps

A couple flicker tests didn't wait and this may lead to flakiness. Force wait for window/activity visibility + animation idle to make the tests more stable

Test: atest FlickerTests WMShellFlickerTests
Bug: 190561000
Change-Id: I52056a0abfd5df6c9c028003cd8fb9b3940b19c0