Use frontend stateMachineState only (no auth) when deciding what page to render

[kshen0]

From discussion #3981 (comment)

VxMarkScan uses a mix of machine state from the backend, frontend auth status, and frontend routing to manage the voting flow. It's becoming too complicated to follow without a single clear owner of routing logic. We should migrate the entire voting flow to live under a single component with a single switch statement that handles all state machine states.

This might be dependent on #3899