Don't send onDeviceDisappeared when device is connected

Connected devices often stop advertizing but it's
confusing to report them as gone.
In this case we'll rely on the disconnected callback to
properly notify a device being gone.

Bug: 181344542
Test: presubmit
Change-Id: I30af50c0cd2a19ec5b91d52801eafa46e62a7010
1 file changed