Remove Brave software links from urlbar suggestions

fix #7655

Auditors: @bsclifton

Test Plan:
1. open a clean instance of brave
2. type 'face' into the urlbar
3. it should autocomplete to facebook instead of Brave's facebook page

app/sessionStore.js

@@ -36,20 +36,6 @@ const getSetting = require('../js/settings').getSetting
 const promisify = require('../js/lib/promisify')
 const sessionStorageName = `session-store-${sessionStorageVersion}`
 
-const getTopSiteMap = () => {
-  if (Array.isArray(topSites) && topSites.length) {
-    let siteMap = {}
-    let order = 0
-    topSites.forEach((site) => {
-      let key = siteUtil.getSiteKey(Immutable.fromJS(site))
-      site.order = order++
-      siteMap[key] = site
-    })
-    return siteMap
-  }
-  return {}
-}
-
 const getStoragePath = () => {
   return path.join(app.getPath('userData'), sessionStorageName)
 }
@@ -524,7 +510,7 @@ module.exports.defaultAppState = () => {
     sync: {
       lastFetchTimestamp: 0
     },
-    sites: getTopSiteMap(),
+    sites: {},
     tabs: [],
     windows: [],
     extensions: {},