Fixed battery chart flickering

- Hide the hourly chart view by default to avoid the calculate the
  space.
- Remove the alpha animation in chart group which causes the flickering
  when open the battery page.

Bug: 378997970
Flag: EXEMPT bugfix
Test: atest BatteryChartPreferenceControllerTest
Change-Id: I1b7e5f74fe63ebcae9f9737b0797d870fd56b134

res/layout/battery_chart_graph.xml

@@ -36,8 +36,7 @@
         android:id="@+id/battery_chart_group"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        android:orientation="vertical"
-        android:alpha="0">
+        android:orientation="vertical">
         <com.android.settings.fuelgauge.batteryusage.BatteryChartView
             android:id="@+id/daily_battery_chart"
             android:layout_width="match_parent"
@@ -53,7 +52,7 @@
             android:layout_width="match_parent"
             android:layout_height="@dimen/chartview_layout_height"
             android:layout_marginBottom="16dp"
-            android:visibility="visible"
+            android:visibility="gone"
             android:contentDescription="@string/hourly_battery_usage_chart"
             android:textAppearance="?android:attr/textAppearanceSmall"
             settings:textColor="?android:attr/textColorSecondary" />

src/com/android/settings/fuelgauge/batteryusage/BatteryChartPreferenceController.java

@@ -274,7 +274,6 @@ public class BatteryChartPreferenceController extends AbstractPreferenceControll
         }
         if (mDailyChartView != dailyChartView || mHourlyChartView != hourlyChartView) {
             mHandler.post(() -> setBatteryChartViewInner(dailyChartView, hourlyChartView));
-            animateBatteryChartViewGroup();
         }
         if (mBatteryChartViewGroup != null) {
             final View grandparentView = (View) mBatteryChartViewGroup.getParent();