[FSA] Update file_system_site_entry element format

Updates the file system Site Settings UI
`file_system_site_entry` element to match the approved UX
mockup in terms of element spacing and layout on the page, while also
matching the layout of the similar `category_setting_exceptions`
element, which appears directly above it.

This cleanup is a required part of the FSA Persistent Permissions
feature implementation.

Screenshot: https://screenshot.googleplex.com/TwJERJCR82nQagU
Bug: 1011533
Change-Id: If7730552b8e650032f6e49141ed74b30962b7367
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4969361
Auto-Submit: Christine Smith <christinesm@chromium.org>
Reviewed-by: Rainhard Findling <rainhard@chromium.org>
Commit-Queue: Rainhard Findling <rainhard@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1216851}

chrome/browser/resources/settings/site_settings/file_system_site_entry.html

@@ -1,18 +1,30 @@
 <style include="cr-shared-style settings-shared">
+  .origin {
+    flex-grow: 1;
+    padding-inline-start: 20px;
+  }
+
   .origin-row {
     align-items: center;
     display: flex;
-    margin-left: auto;
-    padding-right: 0.5em;
+    padding-bottom: 5px;
+    padding-inline-end: 10px;
+    padding-top: 5px;
+  }
+
+  .subpage-arrow {
+    margin-inline-end: 2px;
+  }
+
+  .separator {
+    padding-inline-end: 25px;
   }
 </style>
 
 <div class="list-frame">
   <div class="origin-row">
     <site-favicon url="[[grantsPerOrigin.origin]]"></site-favicon>
-    <div class="cr-row">
-      [[grantsPerOrigin.origin]]
-    </div>
+    <div class="origin">[[grantsPerOrigin.origin]]</div>
     <cr-icon-button id="fileSystemSiteDetails"
         class="subpage-arrow"
         aria-label$="[[grantsPerOrigin.origin]]"