Fix chrome://network CSS for cr-network-icom

BUG=455499

Review URL: https://codereview.chromium.org/972223002

Cr-Commit-Position: refs/heads/master@{#318978}

chrome/browser/resources/chromeos/network_ui/network_ui.css

@@ -50,11 +50,6 @@ paper-button[raised].colored {
   font-weight: bold;
 }
 
-.state-table-icon-cell {
-  display: flex;
-  justify-content: center;
-}
-
 .state-table-expand-button-cell {
   text-align: center;
 }

ui/webui/resources/cr_elements/cr_network_icon/cr_network_icon.css

@@ -2,8 +2,10 @@
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file. */
 
+/* Note: we use display: block here to avoid positioning issues related to
+   the use of overflow: hidden. */
 :host {
-  display: inline-block;
+  display: block;
   height: 50px;
   overflow: hidden;
   position: relative;