Bug 1685310 - Update Top Sites icons for new version of Baidu logo. r=dao, a=jcristau

Use a non-transparent version for the search engine favicon.

Differential Revision: https://phabricator.services.mozilla.com/D100937

browser/components/newtab/data/content/tippytop/top_sites.json

@@ -27,7 +27,7 @@
     "title": "baidu",
     "url": "https://www.baidu.com/",
     "image_url": "images/baidu-com@2x.png",
-    "favicon_url": "favicons/baidu-com.ico"
+    "favicon_url": "favicons/baidu-com.png"
   },
   {
     "title": "bbc",