* Delete unused code
* Run threebox imports through migrations
* Remove 3box feature flag
* Remove unnecessary use of 'type' in threebox._updatePlugin
* Fix threebox controller getLastUpdated
* Turn off threebox by default
* Rename restoredFromThreeBox to showRestorePrompt
* Remove accientally added method from threebox controller
* Restore from threebox on import from unlock screen
* Throw on non 404 errors from Box.getconfig in new3Box
The back button on the import seed phrase page leaves the Redux store
with `appState.forgottenPassword` set to true, which prevents the user
from logging in. That flag is now unset when the user leaves the page.
Fixes#6740
Mark Stacey
Whymarrh Whitby
Dan J Miller
Chi Kei Chan