The dashboard of a site that requires two-step sign-in (MishkaCmsCore.Accounts.SecondFactor.policy/1),
for an admin who has not set an authenticator up (SecondFactor.owed?/1): every page but the
settings page's Preferences tab sends them there, with a flash saying why. An on_mount of every
admin page — see MishkaCmsCore.ExtensionLiveView.
The settings page's other tabs are live patches, which mount nothing, so they are asked again on
handle_params, of the account as stored: setting the authenticator up on that same page opens
the rest of the dashboard without a reload.