Make some display related slices public.

Only PreferenceControllers with isPublicSlice() set to true are exposed
to other apps. Others will be Settings only.

Bug: 141088937
Test: robotests
Change-Id: I2a36da4ac4bb14a4d2ac7b89ab2bb3ebf8e655f7

tests/robotests/src/com/android/settings/display/AdaptiveSleepPreferenceControllerTest.java

@@ -133,10 +133,10 @@ public class AdaptiveSleepPreferenceControllerTest {
     }
 
     @Test
-    public void isSliceable_returnsFalse() {
+    public void isSliceable_returnsTrue() {
         final AdaptiveSleepPreferenceController controller =
                 new AdaptiveSleepPreferenceController(mContext, "any_key");
-        assertThat(controller.isSliceable()).isFalse();
+        assertThat(controller.isSliceable()).isTrue();
     }
 
     @Test