Orca sent `X-Api-Key: 88888888` to Moonraker whenever the printer preset's API Key was empty, which Moonraker rejects with HTTP 401 since Arksine/moonraker@93f5d9c. The preset's API Key is now the only thing that sets the header, and an empty key sends none.
Logging out of a printer now marks it revoked rather than only clearing its code, since an empty code is a valid Moonraker binding. Discovery events are delivered through the network agent and dropped if their printer agent was replaced while queued.
