Remove unnecessary notify in BT preference

notifyHierarchyChanged() is used before when we have
connected/disconnect deivce in same list. So only use it in
DevicePickerFragment.java, not other normal fragments.

Also that call will rebuild whole preference list, which is heavy.

Bug: 119479725
Test: Manual
Change-Id: I06cf221588001b38634fec9f02dee8bc1e561ea8