Add some logging about stack visibility in app bubble logs

I'm stuck on this bug and one of my theories is that the stack might
be invisible due to the shade state (b/314124017#comment41).

This info is already part of the dumpsys but that info is collected
during the bugreport and the shade state might have changed by then
so I'm logging at the time the app bubble is added.

Test: manual - add an app bubble and observe logs
Bug: 314124017
Change-Id: Ib5a16104ba0681b99cff11fddf654df9db0560e9