Add toggle in menu to show/hide hidden apps

In the previous cl we hide unrelated apps and distribute hidden
battery usage among other apps. Now we add a toggle in menu to
show old power accounting as well.

Bug: 35366708
Test: RunSettingsRoboTests
Change-Id: I6918b7095cf84d9756ad3972ff50a62aeae1de0e

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

@@ -46,4 +46,9 @@ public interface PowerUsageFeatureProvider {
    * Check whether it is type service
    */
   boolean isTypeService(String[] packages);
+
+  /**
+   * Check whether the toggle for power accounting is enabled
+   */
+  boolean isPowerAccountingToggleEnabled();
 }