Remove duplicate mojom.dart files from mojo_services

mojo/dart/mojo_services/BUILD.gn

 # Copyright 2015 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/dart/rules.gni")
 
 dart_pkg("mojo_services") {
   sources = [
     "CHANGELOG.md",
     "README.md",
     "pubspec.yaml",
   ]
 
   deps = [
     "//mojo/services",
-    "//mojo/public/interfaces",
   ]
 }