Remove isChartGraphEnabled() which should always return true after

migration.

Bug: 253395332
Test: make RunSettingsRoboTests + manually
Change-Id: I0c4a6e00a7a9fd66d4050e5ddcf87176462067cd

src/com/android/settings/fuelgauge/PowerUsageFeatureProviderImpl.java

@@ -138,11 +138,6 @@ public class PowerUsageFeatureProviderImpl implements PowerUsageFeatureProvider
                 com.android.internal.R.bool.config_smart_battery_available);
     }
 
-    @Override
-    public boolean isChartGraphEnabled(Context context) {
-        return false;
-    }
-
     @Override
     public boolean isChartGraphSlotsEnabled(Context context) {
         return false;