multiple invite bug

[Hgallien]

• [x] P1 can send multiple invite to P2 and all of them can be accepted and start game
• [x] if P1 invite P2 and P3, if P2 accept P1 and P2 play but P3 can accept wihout error
• [x] if P1 and P2 play P3 observe, if P4 invite P3 in a game, P3 can accept but still observe and P4 will be in a bugged game
• [x] if P1 and P2 play p3 can invite P1 btu will play alone
• [x] if P1 go in matchmaking twice he can play with himself and it create a database error
• [x] minor bug, if you receive a invite and you have multiple tab, if you accept in one you can't accept on another tab but the invitation message stay