Remove redundant methods and refactor

Remove the summary method and write the code in AOSP directly instead to
force string consistency. Also refactor a bit after the modification.

Fixes: 276399056
Test: robotests
Change-Id: I76ad740b694363a3cdfb3748e41c840fb678b93d

tests/spa_unit/src/com/android/settings/testutils/FakeFeatureFactory.kt

@@ -84,9 +84,7 @@ class FakeFeatureFactory : FeatureFactory() {
         TODO("Not yet implemented")
     }
 
-    override fun getBatterySettingsFeatureProvider(
-        context: Context?,
-    ): BatterySettingsFeatureProvider {
+    override fun getBatterySettingsFeatureProvider(): BatterySettingsFeatureProvider {
         TODO("Not yet implemented")
     }