Remove setAssistOnly() from GestureSettings

Fix issue that use(AssistGestureSettingsPreferenceController.class)
could be null.

Bug: 287566056
Test: manually - on System > Gestures page
Change-Id: Ifb78a787c34e2fd0e255a6473b8c514f2788f52e

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

@@ -53,7 +53,6 @@ public class GestureSettings extends DashboardFragment {
     @Override
     public void onAttach(Context context) {
         super.onAttach(context);
-        use(AssistGestureSettingsPreferenceController.class).setAssistOnly(false);
         use(PickupGesturePreferenceController.class).setConfig(getConfig(context));
         use(DoubleTapScreenPreferenceController.class).setConfig(getConfig(context));
     }