Avoid resetting the zoom on the sync confirmation and sign-in error dialogs.

chrome/browser/resources/signin/signin_shared_css.html

 <!-- Common styles for signin-related tab modal dialogs. -->
 <dom-module id="signin-dialog-shared">
   <template>
     <style>
       a {
         color: var(--google-blue-700);
         text-decoration: none;
       }
 
       body {
         margin: 0;
         padding: 0;
-        zoom: reset;
       }
 
       paper-button {
         font-weight: 500;
         line-height: 16px;
         margin: 0;
         padding: 8px 16px;
       }
 
       paper-button.primary-action {
@@ skipping 42 matching lines @@
 <if expr="is_macosx or is_linux">
       .action-container {
         flex-flow: row-reverse;
         justify-content: flex-start;
       }
 </if>
 
     </style>
   </template>
 </dom-module>