This reverts commit f5265c24ab.
Apparently it wasn't unnecessary after all. The Lock page served a few
different purposes. First, it was used to safeguard the seed phrase, in
case the user was interrupted after setting a password. Otherwise
anyone could open MetaMask and see the seed phrase without verifying
the password. Second, the submit function for the initialization unlock
screen also returned the seed phrase, so that it could be set in React
state for the confirmation step. Third, the submit function was also
responsible for navigating back to the seed phrase reveal page.
Removing the lock page had the effect of causing an infinite render
loop if onboarding was interrupted in the "Create" flow after setting
a password but before seed phrase confirmation. That redirect loop has
now been fixed.
This page appears to serve the sole purpose of locking the extension
and redirecting back to the base route if the page is refreshed during
the onboarding flow. This ineffectual before the vault has been
initialized, and it's a barrier to resuming interrupted onboarding
flows when done after initialization.
