Don't reupload bookmarks to Sync every load

Fix #8408

Auditors: @diracdeltas @bbondy

Test Plan:
1. Open Brave and enable Sync.
2. Visit archive.org and bookmark it. Terminal should show that it synced.
3. Close archive.org tab.
4. Restart Brave.
5. Examine terminal. Bookmark shouldn't be re-synced.

app/sync.js

@@ -189,11 +189,19 @@ module.exports.onSyncReady = (isFirstRun, e) => {
    * @param {Immutable.Map} site
    */
   const folderToObjectId = {}
-  const syncBookmark = (site) => {
-    if (!site || (site.get('objectId') && seed.equals(site.get('originalSeed'))) ||
-      folderToObjectId[site.get('folderId')] || !syncUtil.isSyncable('bookmark', site)) {
-      return
+  const shouldSyncBookmark = (site) => {
+    if (!site) { return false }
+    // originalSeed is set on reset to prevent synced bookmarks on a device
+    // from being  re-synced.
+    const originalSeed = site.get('originalSeed')
+    if (site.get('objectId') && (!originalSeed || seed.equals(originalSeed))) {
+      return false
     }
+    if (folderToObjectId[site.get('folderId')]) { return false }
+    return syncUtil.isSyncable('bookmark', site)
+  }
+  const syncBookmark = (site) => {
+    if (!shouldSyncBookmark(site)) { return }
 
     const siteJS = site.toJS()