Allow Dupe Mods When Some Are Disabled

[BakersDozenBagels]

Having multiple versions of the same mod in Mods will cause all but one of them to fail to load, even if the duplicates are disabled. This can be useful to rapidly test different versions of mods.

[Aurelius7309]

Added in #1291, UI that makes use of this will follow but needs a rework of the mods menu.