[BUG] Tournament code allowedParticipants does not validate players when joining tournament match

[perdidao]

Bug Description
Any player can join a tournament match with the code that was created for specific puuids.

Problem Description
When creating a tournament match for 2 teams with 5 players, all 10 puuids are provided with the allowedParticipants key through an array, as mentioned on the endpoint docs. Although the codes are successfully generated, any player that is not listed on the allowedParticipants can join with one of the codes.

Expected Result
We expect that if a player that is not included on the 10 puuids tries to access that match with a valid code, the client prevent that player from entering the lobby.

Actual Result
As of now, any player with a given code can join the party even if it's not on the allowedParticipants array provided by the code generation API endpoint.

Developer Impact
It causes a lack of control for our league ops team by allowing rogue players to access tournament matches

• Frequency: Every API call
• Severity: Every single tournament matches can be compromised
• Cost: Intangible since we end up limiting the number of tournaments we run.
• Efficiency: Highly increases the workload for our league ops team

Player Impact
It impacts directly on the tournament credibility since non-listed players can join any tournament match if they have access to the code.

• Frequency: Every tournament match
• Severity: Every yournament matche may be compromised
• Quantity: All players that are enlisted on the tournament.
• Region: This affects all players from all tournaments that uses the americas API

Repro Steps

1. POST to [/lol/tournament/v5/codes](https://developer.riotgames.com/apis#tournament-v5/POST_createTournamentCode) with a valid payload, including the allowedParticipants array of puuids
2. Open the LoL client and use one of the provided join codes to join the party
3. Any player, even if not listed on allowedParticipants, can join the party with one of the codes.

[geozukunft]

Related/"Duplicate" of #828

[carlosviol]

+1