Support rtl for quick scrub onboarding text.

Change-Id: I1f2073e1c24a24aa5ddfd061a6e8b0eaef40335c
Fixes: 80257508
Test: Manual test

packages/SystemUI/res/values-ldrtl/strings.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+/**
+ * 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.
+ */
+-->
+<resources>
+    <!-- Recents: Text that shows above the navigation bar after launching several apps. [CHAR LIMIT=NONE] -->
+    <string name="recents_quick_scrub_onboarding">Drag left to quickly switch apps</string>
+</resources>