fix: Class `VeryGoodFlameGame` does not assume app name

[renancaraujo]

Description

When generating the template with a game named, for example, "My Fun Game", the class VeryGoodFlameGame keeps its raw name rather than assuming the name of the game when it should be MyFunGame.

This is the brick location:

https://github.com/VeryGoodOpenSource/very_good_flame_game/blob/main/brick/__brick__/%7B%7Bproject_name.snakeCase()%7D%7D/lib/game/%7B%7Bproject_name.snakeCase()%7D%7D.dart#L8

Observe that the file name assimes project_name.snakeCase() but the class doesnt.