Pulling poll worker card during paper load state, before paper is loaded, should end the session

[kshen0]

If the poll worker card is removed during the paper load state, the frontend advances to the "Begin Voting" screen.

Ignore the note below. Now that we poll for auth in the state machine this is a fast fix.

--

It's a little tricky to handle this in the state machine because the state machine doesn't subscribe to auth changes. We can handle in the frontend by checking for the accepting_paper state in app_root where we render the Ballot like

if (stateMachineState === 'accepting_paper') {
  return <NoPaperLoadedPage />;
}

return <BallotContext.Provider> ...
</BallotContextProvider>