Usable on tool rack bug fix

Looks like we're supposed to be able to place GT mallets on the tool rack but the wrong item tag is being used.

```javascript

// File path: kubejs/server_scripts/tags/item_tags.js
// Remove "soft" on Line 257
event.add('tfc:usable_on_tool_rack',`${id}_mallet`)
``` 

This fixes the ability to place any GT mallets on TFC tool racks