Update language to comply with Android's inclusive language guidance

Refactor PowerWhitelistBackend to PowerAllowlistBackend
See https://source.android.com/setup/contribute/respectful-code for reference

Bug: 161896447
Test: robotest & manual
Change-Id: I3d56e6dac1515b49a89f59c34edf403ecb891420

tests/robotests/src/com/android/settings/testutils/shadow/ShadowPowerWhitelistBackend.java

@@ -1,28 +0,0 @@
-/*
- * Copyright (C) 2018 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.settings.testutils.shadow;
-
-import com.android.settingslib.fuelgauge.PowerWhitelistBackend;
-
-import org.robolectric.annotation.Implements;
-
-@Implements(PowerWhitelistBackend.class)
-public class ShadowPowerWhitelistBackend {
-    protected void __constructor__() {
-        // Do nothing
-    }
-}