[Toast] Switch to using device config to control keyboard sync.

Bug: 234812580
Test: followed the existing pattern and tested by manually setting and
unsetting the flag through command line - `adb shell device_config put
launcher enable_web_suggest_on_default_browser <true|false>`

Change-Id: Idd479e93b628b78fdf55d826c56f69c5cfdaf46e
diff --git a/src/com/android/launcher3/Launcher.java b/src/com/android/launcher3/Launcher.java
index a6831aa..5be63e3 100644
--- a/src/com/android/launcher3/Launcher.java
+++ b/src/com/android/launcher3/Launcher.java
@@ -1579,6 +1579,14 @@
         return mOldConfig.orientation;
     }
 
+    /**
+     * Whether keyboard sync is enabled for transitions between Home and All Apps.
+     * TODO(b/251387263): move this method inside an All Apps specific config class.
+     */
+    public boolean isKeyboardSyncEnabled() {
+        return false;
+    }
+
     @Override
     protected void onNewIntent(Intent intent) {
         if (Utilities.IS_RUNNING_IN_TEST_HARNESS) {