Extensions still show __MSG__ under description after enabling

[srirambv]

Test plan:

#8314 (comment)

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

• Describe the issue you encountered:
  Extensions still show MSG under description

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

• Brave Version (revision SHA):
  Brave 0.14.2
  rev d4cad89

• Steps to reproduce:

  1. Do a clean install of 0.14.2 RC1
  2. Enable Pocket, wait for the tab to load, extension description shows MSG
  3. Same issue for Dashlane, Lastpass

• Screenshot if needed:
  

• Any related issues:
  Dashlane Password manager shows __MSG_ExtensionName__ as extension name #7683 bitwarden: unknown title and description on about:extensions #7826
  cc: @jonathansampson @cezaraugusto

[cezaraugusto]

@jonathansampson is it possible that d4cad89 reintroduced it?

[jonathansampson]

@cezaraugusto It is; I see the problem now. I'll issue a fix immediately.