[ENHANCEMENT] Open PauseSubState on PlayState Focus Loss

[CrusherNotDrip]

This PR makes it so it opens the PauseSubState when the game loses focus on PlayState.

This is helpful in a scenario where before this pr, they might just mess up as they dive immediately right back into the game if they didn't pause already. After this pr, if the player unfocused the game, it will pause the game helping them prepare to hit their keys again and they don't funk up their current progress in the song.