Remove @Ignore for tests in settings/panel after testing.
Also update VolumePanelTest according to the recent changes to
remote volume slice.
Test: atest PanelFragmentTest
Test: atest SettingsPanelActivityTest
Test: VolumePanelTest
Fixes: 130896218
Change-Id: Iaa99e65d959cafd382d7209664f2fdbf660c29e0