This was done to reduce the number of direct dependencies we have. It
should be functionally equivalent. The bundle size should not change,
as we use `clone` as a transitive dependency in a number of places.
The `seedWords` state was removed from the PreferencesController
recently in #6920. That state hadn't been used in some time, and there
was a long period during which `seedWords` was periodically scrubbed
from the state, so it's highly unlikely that it still exists in state
for most users. It's hard to guarantee that it _doesn't_ though,
especially if a user hasn't opened MetaMask in a few months.
