Refactor background optimization mode in Power Usage Detail page.

[Screenshot]:
before: https://screenshot.googleplex.com/6m5jYWHofY2pFov

after:
[App battery usage]
- [normal] https://screenshot.googleplex.com/7aurWk7cHKaWds7
- [always unrestried/optimized] https://screenshot.googleplex.com/3rGAh4ccUYTKBAr

[Allow Background usage]
- [Restricted]: https://screenshot.googleplex.com/MPXjQe5kPWw2nhr
- [Optimized]: https://screenshot.googleplex.com/6w4zTT6r34APnGc
- [Unrestricted]: https://screenshot.googleplex.com/97FgvHWMrwASqYH

Bug: 302063050
Bug: 306295660
Bug: 308359833
Test: manual
Change-Id: I3237d015549fe26e62d6d68c13403cc2cbdf0017

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

@@ -31,10 +31,8 @@ import android.content.Context;
 import android.content.Intent;
 import android.content.pm.PackageManager;
 import android.os.UserHandle;
-import android.os.UserManager;
 
 import com.android.settings.TestUtils;
-import com.android.settings.fuelgauge.BatteryOptimizeHistoricalLogEntry;
 import com.android.settings.fuelgauge.batterysaver.BatterySaverScheduleRadioButtonsController;
 
 import org.junit.After;
@@ -75,6 +73,7 @@ public final class BatterySettingsMigrateCheckerTest {
     public void setUp() throws Exception {
         MockitoAnnotations.initMocks(this);
         mContext = spy(RuntimeEnvironment.application);
+        BatteryUtils.getInstance(mContext).reset();
         doReturn(mContext).when(mContext).getApplicationContext();
         doReturn(mPackageManager).when(mContext).getPackageManager();
         doReturn(UID).when(mPackageManager)