[Client] Game starts without checking if all players are online

In other words if you selected a champion and terminate league via taskmgr, have a power outage or disconnect from the internet the game will still start without the player being aware of it.

TLDR: Riot's spaghetti software doesnt check if all players are connected when starting the game, leading to many 4vs5.

major bug being for years in the client and probably ruining the expierence for thousands of players (starting a game 4vs5 is simply obnoxious)