[SUGGESTION] Allow for Custom Model Data to be used for icons

[Coswics]

Just a Small QOL thing, but allowing custom model data to be inputted for item appearances in the GUI would be great! since a lot of items dont match icons perfectly (done via resourcepacks)

[ImCodist]

I'd be happy to implement this!

[ImCodist]

Implemented in commit 3911a6a.
Can be changed in the advanced options category in the action editor.