Enable use_once_callback on mojom GN rule by default

device/bluetooth/public/interfaces/BUILD.gn

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//mojo/public/tools/bindings/mojom.gni")
 
 mojom("interfaces") {
   sources = [
     "uuid.mojom",
   ]
 }
 
 mojom("fake_bluetooth_interfaces") {
   sources = [
     "test/fake_bluetooth.mojom",
   ]
-
-  use_once_callback = true
 }
 
 mojom("experimental_interfaces") {
   sources = [
     "adapter.mojom",
     "device.mojom",
   ]
 
   public_deps = [
     ":interfaces",
   ]
 
   visibility = [
     "//device/bluetooth:mojo",
     "//chrome/browser:*",
     "//chrome/browser/ui:*",
   ]
-
-  use_once_callback = true
 }