Old experimental worlds are still labeled "Experimental"

Summary:

Despite the fact that the "Caves and Cliffs" switch no longer exists. Old experimental worlds are still labeled "Experimental".

Steps to reproduce:

1. Enter the game.
2. Look at the line below the name of your old world with "Caves and Cliffs" previously included.
3. Try to find the switch in the world settings.

Observed results:

"Caves and Cliffs" no longer exists, and the label still remains.

Expected results:

The Experimental label will be removed.