Pressing "Down" on crafting list order can crash AT

[filliph]

Describe the bug If a crafting list has an order of 1 and you press the Down button, Allagan Tools will pop up a window saying it encountered an error and that I should restart the game.

To Reproduce Steps to reproduce the behavior:

1. Open /atconfig interface
2. Press "Down" on the remaining list when its order is 1
3. See error

Expected behavior Either the button to disappear or for nothing to happen when you click it.

Dalamud Information: Testing is not enabled.

Additional context This only occurs when you have only one crafting list.