Currently we create Always on Display slice through AmbientDisplayAlwaysOnPreferenceController. However, as the Always on Display is merged into Idle lock screen, the conversion won't work properly anymore when devices support the aware sensor. Hence, we create another custom slice for this purpose. Bug: 145920511 Test: manual & robotest Change-Id: Ifd90e2de5219bd4e97aa13b5855fdab95ff6c4d0