The game now crashes when attempting to create a new world while the saves folder is not present

The issue I previously reported in MC-308184 was not completely fixed.
When the game starts and you click "Singleplayer", the game checks whether the .minecraft/saves folder exists. However, if the .minecraft/saves folder is deleted while the world selection screen is already open, clicking "Create New World" can still crash the game.

Steps to reproduce:

1. Launch the game and open the Singleplayer screen.

2. Delete the .minecraft/saves folder without closing the world selection screen.

3. Click "Create New World".

4. The game crashes.

Expected:

Game should handle missing saves folder gracefully and not crash.

Actual:

Game crashes when clicking "Create New World" after saves folder is deleted.