"Backed up" toast does not use world name

When backing up a world, the toast message uses the world folder name instead of the world name (from level.dat). This is despite the world name being used in all other parts of the GUI to refer to the world.

Steps to reproduce

1. Find a world where the world folder name is different to the world name

2. Make an in-game backup of the world

Observed behaviour

The toast uses the name of the world folder

Expected behaviour

The toast would use the user-specified world name

Screenshots

World name is "The void..."