Index SliceType and Official Platform flag

Extend slices_index.db to include SliceType and platform flag.
This will be used when we generate a list of all available slices
for different authorities & separated intent/action paths.

Bug: 62807132
Test: robotests
Change-Id: I1cce49d077c02ab79153db9bfdfc894dbab5e16a

tests/robotests/src/com/android/settings/slices/SlicesDatabaseHelperTest.java

@@ -68,7 +68,9 @@ public class SlicesDatabaseHelperTest {
                 IndexColumns.SCREENTITLE,
                 IndexColumns.ICON_RESOURCE,
                 IndexColumns.FRAGMENT,
-                IndexColumns.CONTROLLER
+                IndexColumns.CONTROLLER,
+                IndexColumns.PLATFORM_SLICE,
+                IndexColumns.SLICE_TYPE,
         };
 
         assertThat(columnNames).isEqualTo(expectedNames);