MD Settings: consolidate learn-more link styles

BUG=649427
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2628773004
Cr-Commit-Position: refs/heads/master@{#443298}

chrome/browser/resources/settings/reset_page/powerwash_dialog.html

@@ -9,10 +9,6 @@
 <dom-module id="settings-powerwash-dialog">
   <template>
     <style include="settings-shared">
-      a {
-        color: rgb(66, 133, 244);
-        text-decoration: none;
-      }
     </style>
     <dialog is="cr-dialog" id="dialog">
       <div class="title">$i18n{powerwashDialogTitle}</div>

chrome/browser/resources/settings/reset_page/reset_profile_dialog.html

@@ -14,8 +14,6 @@
   <template>
     <style include="settings-shared">
       .footer a {
-        color: rgb(66, 133, 244);
-        text-decoration: none;
         vertical-align: middle;
       }