[MD settings] removing .css files from internet settings

chrome/browser/resources/settings/internet_page/network_siminfo.css

-/* 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. */
-
-iron-icon {
- -webkit-margin-end: 5px;
- -webkit-margin-start: -3px;
-}
-
-paper-button {
-  margin: 0;
-}
-
-span {
-  -webkit-margin-end: 10px;
-}
-
-#lockedDiv span {
-  color: red;
-  font-weight: 500;
-}
-
-#lockedDiv paper-input {
-  -webkit-margin-start: 10px;
-  width: 80px;
-}
-
-#unlockSimDialog paper-input {
-  -webkit-margin-start: 5px;
-}
-
-#unlockSimDialog span {
-  -webkit-margin-start: 5px;
-}
-
-.pin {
-  min-width: 100px;
-}
-
-.puk {
-  min-width: 200px;
-}
-
-.error {
-  color: red;
-  max-width: 400px;
-}