Deleting engine go key doesn't remove the Search engine icon from URL bar

[srirambv]

Did you search for similar issues before submitting this one?
Yes

Describe the issue you encountered:
Deleting engine go key doesn't remove the Search engine icon from URL bar

Expected behavior:
Should remove the search engine icon and replace with magnifier icon

• Platform (Win7, 8, 10? macOS? Linux distro?):
  Windows 10 x64

• Brave Version (revision SHA):
  Brave 0.13.0
  rev dc4f0fd
  Verified on 0.12.15, pressing back space changes the search engine icon to magnifier icon

• Steps to reproduce:

  1. Open a new tab
  2. Type any of the search engine go key and press space to show the search engine favicon in URL bar
  3. Press back space and delete the engine go key, but icon still remains

• Screenshot if needed:
  

• Any related issues:
  cc: @bsclifton

[bbondy]

I'll take, probably from the refactor.