Disable AssistGestureSetting search if not supported

Change-Id: Id5f79506635592d98783b2b99b7ee09dd223c43c
Fixes: 64066820
Test: robotests

src/com/android/settings/gestures/AssistGestureSettings.java

@@ -79,9 +79,17 @@ public class AssistGestureSettings extends DashboardFragment {
                 }
 
                 @Override
-                public List<AbstractPreferenceController> getPreferenceControllers(Context context) {
+                public List<AbstractPreferenceController> getPreferenceControllers(
+                        Context context) {
                     return buildPreferenceControllers(context, null /* lifecycle */);
                 }
+
+                @Override
+                protected boolean isPageSearchEnabled(Context context) {
+                    return new AssistGesturePreferenceController(context, null /* lifecycle */,
+                            null /* key */, false /* assistOnly */)
+                            .isAvailable();
+                }
             };
 }