Clean up: remove preference_category_no_title.

We already have a custom category layout that does the same thing.

Test: visual
Change-Id: Ice6daea8b2d9a14e9b013cf4175ce00f5ab1cc8d

res/layout/preference_category_no_title.xml

@@ -1,27 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!-- Copyright (C) 2017 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.
--->
-
-<!-- Based off frameworks/base/core/res/res/layout/preference_category_material.xml however
-     set height to 0. This will be used in preference category without title in order to remove
-     extra 32dp blank -->
-<TextView xmlns:android="http://schemas.android.com/apk/res/android"
-    android:id="@android:id/title"
-    android:layout_width="match_parent"
-    android:layout_height="0dp"
-    android:textAppearance="@android:style/TextAppearance.Material.Body2"
-    android:textColor="?android:attr/colorAccent"
-    android:paddingStart="?android:attr/listPreferredItemPaddingStart"
-    android:paddingEnd="?android:attr/listPreferredItemPaddingEnd" />

res/xml/power_usage_summary.xml

@@ -28,7 +28,7 @@
 
     <PreferenceCategory
         android:key="battery_tip"
-        android:layout="@layout/preference_category_no_title" />
+        android:layout="@layout/preference_category_no_label" />
 
     <Preference
         android:fragment="com.android.settings.fuelgauge.batterysaver.BatterySaverSettings"