[DevTools] Fix emulation drawer button styles.

Source/devtools/front_end/overrides.css

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 146 matching lines @@
 }
 
 .overrides-device-value-label {
     overflow: hidden;
     white-space: nowrap;
     text-overflow: ellipsis;
     margin-top: 10px;
 }
 
 .overrides-device button {
-    height: 20px;
     margin: 0 3px;
 }
 
 .overrides-device label {
     margin-bottom: 10px;
 }
 
 .overrides-device table {
     margin-bottom: 5px;
 }
@@ skipping 150 matching lines @@
 .overrides-reset-button,
 .overrides-disable-button {
     margin: 9px 0 0 17px;
     display: block;
     width: 60px;
 }
 
 .overrides-enable-button {
     margin: 4px !important;
 }