WebUI Dark Mode: fix Autofill section margin regression

R=hcarmona@chromium.org
BUG=925278

Change-Id: Ia5c5f4770609a3794737732188312b5da4ebc43a
Reviewed-on: https://chromium-review.googlesource.com/c/1437272
Auto-Submit: Dan Beam (slow until 1/29) <dbeam@chromium.org>
Commit-Queue: Hector Carmona <hcarmona@chromium.org>
Reviewed-by: Hector Carmona <hcarmona@chromium.org>
Cr-Commit-Position: refs/heads/master@{#626274}

chrome/browser/resources/settings/autofill_page/autofill_page.html

@@ -16,8 +16,10 @@
 <dom-module id="settings-autofill-page">
   <template>
     <style include="settings-shared">
-      cr-link-row:not([hidden]) + cr-link-row {
+      cr-link-row {
         --cr-icon-button-margin-start: 20px;
+      }
+      cr-link-row:not([hidden]) + cr-link-row {
         border-top: var(--settings-separator-line);
       }
     </style>