[Bug]: Infinite loop between front end and back end if tournament is missing.

[fintanneff]

What went wrong:

When the user tries to access the site in their browser, there is an infinite loop between the front end and the back end if the tournament is missing from the database.

Expected behavior:

An infinite loop should not be possible; I presume there should be some kind of error message presented instead.

[TylerBloom]

The problem here should be fairly simple to fix. When loading a tournament's page, the frontend sends a request to the backend and immediately attempts to deserialize the JSON in the body. If this fails, it sends a new request. This causes the loop. However, the backend doesn't send back a TournamentManager but rather an Option<TournamentManager>. We can simply check if the response is None and not send a request again. In the None case, we should probably show the user a screen like "Tournament not found".