Define a constant Sliceable#NO_RES for no resource cases

Fix: 204733076
Test: build
Change-Id: Ifa3b9db0e915a3ec056ad68a9a1862811594d423

tests/unit/src/com/android/settings/network/ProviderModelSliceHelperTest.java

@@ -305,7 +305,7 @@ public class ProviderModelSliceHelperTest {
 
         @Override
         public int getSliceHighlightMenuRes() {
-            return 0;
+            return NO_RES;
         }
     }
 

tests/unit/src/com/android/settings/slices/SpecialCaseSliceManagerTest.java

@@ -146,7 +146,7 @@ public class SpecialCaseSliceManagerTest {
 
         @Override
         public int getSliceHighlightMenuRes() {
-            return 0;
+            return NO_RES;
         }
     }
 }