1. Iterate all urls using the favicon
2. Adjust made-up-favicon condition and override old made-up-favicon url

fix #4882

Auditors: @bridiver, @bbondy

Test Plan:
1. Import bookmarks from firefox on brave 0.12.3
2. Import bookmarks from firefox on brave contains this commit
3. The bookmarks under "Mozilla Firefox" should have favicons

1. Import bookmarks from any browsers
2. The imported bookmarks should have favicons

1. Import bookmarks from html bookmarks file
2. The imported bookmarks should have favicons