Better diagnose Launcher state when there is an open folder.

Without this change, the diag is:
visible state is LaunchedApp (active app: com.google.android.apps.nexuslauncher)

https://android-build.corp.google.com/test_investigate/?testResultId=TR37728586113816784&invocationId=I13000010147719553&tab=trace

Test: presubmit
Bug: 187761685
Change-Id: Ia2425a09408d7e1a9c22d0a65fc4ab31cc793a46