Update battery summary

When it is charging, show "5% - charging"(not only "5%")

Bug: 112013485
Test: RunSettingsRoboTests
Change-Id: If2299cc4929d8fc40d63669b74590fafe39122dc

tests/robotests/src/com/android/settings/fuelgauge/TopLevelBatteryPreferenceControllerTest.java

@@ -61,5 +61,9 @@ public class TopLevelBatteryPreferenceControllerTest {
 
         info.remainingLabel = "Phone will shut down soon";
         assertThat(getDashboardLabel(mContext, info)).isEqualTo("3% - Phone will shut down soon");
+
+        info.discharging = false;
+        info.chargeLabel = "5% - charging";
+        assertThat(getDashboardLabel(mContext, info)).isEqualTo("5% - charging");
     }
 }