Move spinner_dropdown_restricted_item to Settings.

RestrictedDropdownPreference is in Settings and currently not
used by anything else, so corresponding layout
spinner_dropdown_restricted_item to Settings.

Bug: 28390118
Change-Id: I3a1b53dc80ba9329d6ffd40562db0c0587a34666

packages/SettingsLib/res/layout/spinner_dropdown_restricted_item.xml

@@ -1,22 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!-- Copyright (C) 2016 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.
--->
-<TextView xmlns:android="http://schemas.android.com/apk/res/android"
-        android:id="@android:id/text1"
-        style="?android:attr/spinnerDropDownItemStyle"
-        android:singleLine="true"
-        android:layout_width="wrap_content"
-        android:layout_height="?android:attr/listPreferredItemHeightSmall"
-        android:ellipsize="marquee" />